Category Archives: Battling with Tech

How to do things with your gadgets – usually learned the hard way

Fibre to the premises

I’ve been so busy trying to get the renovated house ship-shape that I’ve neglected this blog.  But now to revert to an old hobby-horse, BT.

About 18 moths ago, I was writing about the impending demise of the aged hard-wired telephone system, the PSTN.  Epsom has a few ‘claims to fame’.  One is that it had the first automatic public exchange in the country, opened just over 100 years ago in 1912.  But its days are numbered.  Epsom been plagued for months by OpenReach vans laying optical fibre to enable ‘fibre to the premises’ service and indeed I got rather upset by ‘Kelly Communications’, who are contractors for OpenReach, festooning cables around and over my garden.

So I was rather expecting the call from BT offering me ‘Fibre to the premises’ giving 500 Mb/s download speed and a somewhat vague upload figure of 75 Mb/s.  The guaranteed speeds are not so impressive (250 Mb/s down and 10 Mb/s up), especially as I’d like a faster upload speeds for videos and so on. The price was £60  per month (£5 more than I’m paying for my present ‘fibre to the cabinet’ but in reality, I would pay slightly less as I’m dropping the ‘unlimited anytime calls’ option as we have made no outgoing calls on the landline for over a year!  Any calls we do make will now be ‘pay-as-you-go’ but as we both have unlimited mobile calling, we’d only use this in exceptional circumstances.

After agreeing to this, I felt rather bullied by all the ‘don’t forget your appointment’ messages:  ‘We are getting ready.  Are you?’

The guy turned up on time, and asked where the master socket was.  When I showed him, there was a look of dismay.  It turns out that they like to terminate the optical fibre on the inside of the house immediately at the point where it enters the premises and to put the optical modem there.  But my downlead wanders around the eaves for a considerable distance round several corners then disappears into the eaves and reappears in a room on the opposite side of the house.  This appears to be a legacy of alterations to the house and the GPO moving the telegraph pole several times during the ninety years since the house was built.  Not ideal as optical fibre isn’t easily jointed and the technician had only been supplied with a limited length.

The other issue is that the optical modem must be close to a power point.  (Some of the BT material talks about a battery backup unit, but he said that the Nokia unit they are fitting doesn’t have this, and there was little point since the router (home hub) needs mains power.)  I noted that BT has switched from Huawei to Nokia, but ironically the Nokia unit is proudly emblazoned ‘Made in China’!)

As it happens, the best and most convenient route is through an eaves cupboard to the ‘office’ where we want the router, but we have had to ask him to come back as we will have to clear a lot of junk from the cupboard, fit a power point and run a Cat 5 Ethernet cable to the office room.  The router can then be fitted in the office.

So what about the telephone service?  There is a socket on the ‘Home Hub’ for ‘Phone’ marked ‘For Digital Voice Customers Only’.  This looks like an ordinary phone socket, so presumably that is where the phone goes and hopefully it can supply enough current to ring my treasured extension bell!  This will mean the end of the power-failure-proof hard-wired phone, but we have been expecting this for some time now.

Annoyingly, clearing the cupboard is another job I have been avoiding, but I suppose it will compel me to get it done.


Scott Adams, the author of the Dilbert cartoons, must take credit for inventing this word.  He uses it to describe the way that marketing departments use deliberate confusion to get people to buy things that don’t do what they intended, or to pay too much for what they do want.

Robert Bosch Ltd

I have to nominate Robert Bosch Ltd in this category.  I’m embarking on some DIY projects – basically building a storage system in my new house extension.  I was going to get the builder to do this, but the Coronavirus lockdown has put all plans awry.  It has taken my builder much longer to complete the work as he was unable to get materials – and this was a genuine problem – and so other customers are pressing him and I decided I could build the storage myself as an interesting project.  However, I haven’t bought any power tools for over twenty years and I noticed that the builders had boxes full for every sort of work.  I decided that a cordless impact drill/ screwdriver and cordless circular saw could speed up the work.  (I’m often told that I take too long to do this sort of thing, but the builders have been very slow – maybe spinning work out during the lockdown.)

I looked around on the internet for buying advice and noted that Robert Bosch has a good 18 volt system with a large variety of DIY and gardening tools, so I could get more things as time goes on.

So then it is a matter of finding an offer at a good price.  This is where the confusopoly starts.  Firstly, their cordless drills come in different battery voltages – 12 v and 18 v.  Then they come in ‘Easy’, ‘Universal’ and ‘Advanced’ ranges. (There is also a separate ‘Professional’ range.)  Then the batteries come in three or four capacity ratings.  Then the tools come with or without batteries and accessories.

And of course, they are all different prices.  So it becomes extremely difficult to work out what you need and even whether you are buying what you intended.  You might choose the cordless combi drill with two batteries for £114 without realising that these are only 1.5 Ah batteries with a low-powered charger as this is only shown in the detailed specification – if you can find it.  And if you search on price, you can easily be confused as to what the battery capacity is, how many are included, what sort of charger you get and what sort of accessories.

So, I ended up with a drill/screwdriver with high-capacity batteries but without the impact function.  The price was fine, so I will keep it, as I have two mains-powered impact drills which will probably be better for some of the heavy-duty drilling.  This happened because whilst looking for the best price, I didn’t notice that they’d substituted an AdvancedDrill 18 for the AdvanceImpactDrill 18 that I’d been searching.

I feel I would have been wiser to buy a deWalt cordless combi drill with two 3.0 Ah batteries and rapid charger for £120.  It comes in a much more rugged case.  Indeed whilst de Walt offer a range, there does seem to be some sense in it, rather than too many options confusing options. Since my builder, who is a canny operator, is using these, there must be something to recommend them.

By the way, I partly criticise Amazon for this.  When you search for something, it comes up with a host of options and the distinction between the offers is often far from clear.

Wiring a new telephone master socket

Determining that the line is live

In the previous post, I explained that BT advised me to instal a new master socket myself.  My builder had installed a 4-pair cable (probably a standard CAT-5 network cable) from the BT drop-wire to my workroom (although I have no idea where the junction box is hidden), and had pushed the white/green pair into an old socket, so I guessed these carried the line. The CAT-5 network cable is not compliant with the UK telephone standard, but no matter.  A telephone line usually only requires a single pair nowadays, although my system originally had an earth connection from an earth rod near the drop wire, but this has long since been disconnected.   Earth wires were originally installed as part of a spark suppression system in the days of long overhead wires and in some cases were used as part of the exchange-calling system on so-called ‘party’ (i.e. shared) lines.

In the idle condition, the network pair carries a potential difference of 50 v DC, with the so-called A-leg being at 0 v and the B-leg at -50 v, relative to earth.  The polarity on the pair only matters in a few special cases, but I wanted to do the job properly, so I measured with a voltmeter to confirm that the line was active and determining that the white/green wire was 0 v (making it the A-leg) and the green wire was at -51.2 v (B-leg), see photo below.  This told me which wire to put into each of the terminals.

Testing the voltage on the A and B legs of the network ‘drop wire’

It is safe to touch the wires, although always wise to avoid this for the reasons I’ve previously mentioned.  However, if someone rings the line whilst you are touching them, you will get a nasty zing, because the ringing voltage is about 75 v AC at 18 Hz.  I believe that now it is around 100 v at possibly slightly higher frequency.  So the peak voltage is √2 times this, i.e. about 140 v, and the peak-to-peak is twice that, so plenty of juice to sting you.   Remember the electrician’s mantra – keep one hand in your pocket!

The NTE-5c Mk 4 master socket
Rear of base-plate with exchange wires connected. Non-standard wire colours – see text.

The NTE5c socket is a clever piece of design. It is in three parts – a standard-sized back-box that is fixed to the wall.  Then the base plate.  The drop wire is connected to a 1-pair cam-lock connector on the back of the base plate, marked A and B. Nothing else. The Base Plate is then fixed to the back-box by two screws.  This demarcates OpenReach’s ownership from the subscriber’s, who is not supposed to remove these screws.

On the front of the base plate is another cam lock connector, this time with three terminals, marked 2, 3 and 5.  They have kept the historical numbering, even though the other wires are no longer used.  Wires 2 and 5 carry the speech  and correspond to legs A and B, whilst wire 3 is the bell wire, and separates the AC ringing current from the DC loop current by means of a capacitor.  The Master Socket also used to have a surge protector across the A and B legs.  This was a small neon tube that would discharge a potential above a few hundred volts, preventing damage to the instrument or a shock to the subscriber, but the gas-filled tube also acts as rather a noisy capacitor at high frequency and thus makes the line noisy for the broadband signal, so it is no longer fitted.  It does mean that there is less surge protection than in the past, but this is much less of an issue than in the days of miles of uninsulated lines carried on overhead poles.  [I was once in a house during a violent thunderstorm when the fuses in the drop-wire junction box blew out.]

Connection of network wires to A and B legs of master socket

You don’t need any tools to connect the wires to the camlock connector. You lift up the clear plastic tab and then, observing polarity, push both wires through the front holes, then making sure to keep them straight,  through the back holes. It’s not quite so easy to keep them in place when fitting three wires – one can easily spring back.  If the wire isn’t through both holes, it may not be properly forced between the terminal prongs when you push the plastic tab back down. I would say this is a slight issue with the camlock connector.

Having connected the network wires into the rear of the back plate, secure it to the back-box with the screws provided.

You will see that there is a socket for a telephone plug on the front of the back plate.  Plug in a standard (non-powered) telephone.  You should get dial tone (you may need to wait a few moments) and be able to make (and receive) a test call.

So your line is working! Excellent.

Connecting the extension wires
Front of base-plate with extension wires connected

Returning to the NTE5c – you, the subscriber, can connect all your hard-wired extensions to the 3-way cam-lock connector on the front of the back-plate.  However, until the front plate is inserted, there is no connection between the exchange line and the subscriber’s wiring.  Instead, if you look carefully at the telephone socket in the back plate, you will see three wires at the bottom which are not connected when inserting an ordinary telephone socket, as these have no pins on the bottom edge. However,   when you plug in the front plate, this has a special plug that connects wires 2, 3 and 5  to the terminals on the front of the back plate, thus connecting your extension wiring to the exchange line.   The beauty of this is that when the front plate is removed, the exchange line is completely disconnected from the rest of the internal wiring, so if you can’t get dial tone from the socket in the back plate, the fault must lie of BT’s side of the system.

The front plate

As I understand it, two types of front plate are available.  One just has an ordinary telephone socket on the front, and the other has a telephone socket and a broadband socket with the necessary filters being built into the front plate, as in the illustration at the top of this post.

As mentioned, the front plate has a special plug that goes into the telephone socket in the back plate, but at the same time, connects the internal wiring circuit to the exchange side of the circuit.  The front plate is kept in place by two spring lugs and can be easily removed by the subscriber.  The idea is that if your line goes down, BT can ask you to remove the front plate (no tools needed) and ask you to plug the phone into the socket in the back plate.  If this works, they know the fault is on your side of the system.  They can then charge you whatever to come and fix it, or no doubt there will be independent firms who can investigate, perhaps more cheaply.

That really is a brilliant wheeze!

Fitting the extension bell wiring
The old-style GPO telephone extension bell with original wiring

The builder had run another 4-core pair to the position of the extension bell.  So I have re-fitted the bell and connected the blue and white-blue pair to terminals 2 and 5, and the orange wire to terminal 3 on the front of the back plate of the master socket.  The extension bell solenoid is connected at the other end to blue and orange wires.  The label in the bell-box states that as connected, the solenoid offers a resistance of 1000 Ohms, which is, I think, below the presently recommended value, but has always worked well.  Possibly it may not be so happy if there were more ‘ringers’ on the circuit.  Having now tested it, it is extremely loud, so there is plenty of current at the bell.

The ringing current

On a related subject, where does the ringing current and all the other system tones come from?  In the old Strowger exchanges, there was a ringing machine at the end of each rack, basically a motor-generator set.  The generator had a number of different windings to generate the necessary tones and a cam-operated set of contacts interrupted the tones to produce the brr-brr ringing cadence.  I can remember having an argument with someone who said to me ‘The phone is ringing at the other end’ and when I said ‘how do you know’, they said ‘I can hear it’.  They just could not understand that the ringing sound they could hear was supplied by the exchange, and was not the bell at the far end!

I hope this gives you a bit of insight into the telephone system and will allow you to instal your own master socket when necessary. Take care as always when working with electricity, especially at height.

BT amazes again!

Broadband connections

Some months ago, I had to switch to mobile broadband whilst I had some building work done. Unexpectedly, the builders had ripped out all my phone wiring!

So the builders have gone and I need my connection to be reinstated.  They got rid of everything, including the phone master socket, although they’d left the extension bell box in a corner because I specially asked.  Luckily the ‘drop wire’ from the network is still there.

Putting in a Master Socket

So I looked up how to put in a Master Socket.  This basically provides a termination to the exchange line and also separates the voice line from the broadband line (through a filter circuit).  Although it’s straightforward, a YouTube video I watched (clearly made a few years back) pointed out that it was illegal to fit a Master Socket yourself.  As I’ve said before, I worked as a student trainee for Post Office Telegraphs and Telephone (as it was then) and I remembered how ‘precious’ they were about it.  In those days, of course, they owned everything including the ‘instrument’ as the phone was called.  Telephones were permanently wired in and you couldn’t fit your own. Your instrument was rented and quite often your line was shared with a neighbour! They would say things like how an idiot householder could accidentally connect the phone line to the mains and this could electrocute a technician.

So I thought, well, I have a lot of things to do in the house, so I guess I will have to bite the bullet and get BT to do it.  Today I called BT and after a long wait got through to a nice girl in Blackburn. ‘Oh’, she said,  ‘Well we could do it for you but it will cost £130.  But you could just buy a socket in a hardware store and do it yourself.’.. ‘Right’, I said, ‘But I thought that was illegal.’  ‘Oh, no.  It’s perfectly fine and easy enough to do if the wiring is still there!’

I was gob-smacked.  So I’ve ordered a very nice ‘genuine Openreach’ NTE5C socket (which probably means Network Termination Equipment’ via Amazon and will look forward to seeing how I get on.  I haven’t yet tested the voltage on the line.  If I remember right, there should be 50 v across the exchange pair as long as the line is still connected.  From experience, you don’t feel this voltage, but it goes up to 75 v (AC) when ringing and this can give you quite a thrill.

I’m going to re-fit the original extension bell box as this is audible in the garden.  Should be fun.

Wait for the next instalment soon!

LED Driver Circuitry

Why choose an LED bulb

My previous post describes some of the considerations involved in using LED bulbs, with some detail on a G4 halogen replacement LED.   I got interested in this when searching online for some LEDs for a new light fitting I’d bought.  This was designed for six 20W 12v halogen bulbs. Reviews such as ‘It’s a pity this only takes 20W bulbs’ made me think that it probably wasn’t all that bright, even though it would use 120 watts.  Naturally, I thought I’d fit the brightest LED bulbs that I could get and after some time trawling the internet, it seemed that 6w bulbs were the highest power available in G4 fittings.  I ordered 10 cool white dimmable.

Needless to say, I’m wary of stuff from China – they always manage to find a way of exaggerating the specification, so when the bulbs arrived, I felt I should investigate a bit more.   This titchy bulb contains some quite sophisticated electronics.

The circuitry

In essence the base contains the circuitry on both sides of a flat board and the top part contains six small LED chips mounted on a rectangular glass substrate with yellow phosphor on both sides of the glass. It is all sealed in a soft, clear plastic resin, so care is needed not to bend it, otherwise the internals will be damaged.

The circuitry inside an LED lamp

Looking at the electronics board, on one side we have what is essentially the input circuitry – the big yellow rectangular blob is a smoothing capacitor and I assume that the rectangular things are  diodes for a bridge rectifier plus some resistors.  Together they create a nice smooth 12 v DC input from the 12 v AC that they are supplied with.  This is fed to the circuitry on the other side.

A 12 v replacement LED

Although I can’t read the designations on the small chip in the middle, it is something like the ZXLD1360 LED driver shown in the circuit diagram below.

Connections to the 1360 regulator chip

In essence, it is a current/voltage regulator that reduces the 12 volt input to that needed to drive the LEDs. Since each of the LED chips will need a forward voltage of around 3.4 volts and the supply is nominally 12 volts, I am rather assuming that the six chips are connected in parallel, as the connecting wires are too small for me to see.

Internal connections of the 1360 regulator chip
How does it work

This chip is in essence a current regulator.  The current to the chain of LEDS is sensed from the potential difference across a resistor (shown as Rs in the circuit diagram)  The circuitry in the chip pulses the main power transistor (MN in the circuit diagram) on and off at high frequency (kilohertz) to maintain the current at the design level.

The small choke L1  acts to smooth the current curve and also improve the power efficiency of the circuit. When the main transistor MN switches off, the magnetic field in the choke collapses  generating a reverse potential across the choke.  This feeds back to the input of the circuit through the  Schottky diode [don’t confuse the ‘S’ symbol on the cathode with the ‘Z’ symbol of a Zener diode: Schottky diodes have about half the forward voltage drop of an ordinary silicon diode] and thus light the LEDs on the reverse half-cycle.

Since there are six LEDs in the bulb, then each must consume 1 watt if it is a six watt lamp, If the lamps are in parallel, then with a voltage of 3.3 v across each one, the current must be 0.3 amps, requiring 1.8 amps for all six lamps.  But the circuit can only provide 1 amp.  I suppose they could be connected three in series (as shown in the circuit diagram) and both of the three in series being connected in parallel.  It is best if they are all connected in series, as this ensures that the same current flows through each, which evens up their brightness.  Sadly, I think it is more likely that they will claim that the ‘W’ doesn’t mean watts at all, but perhaps ‘way’ in other words it has six diodes in it.  I suspect the diodes are not likely to take more than about 100 mA each, if that, so it probably consumes 0.3 watts per diode and maybe 1.8 watts all told.  In other words, quite a lot less bright than the 20 w halogen.  I will measure this when I get access to the 12 v transformer.


Moreover, I’m pretty sure that this will not work with a dimmer – in fact it does its best to maintain the LED current whatever the input voltage, so will resist attempts to dim it.  The chip does actually have a separate dimmer input to it, but this needs an external connection, which obviously you don’t have in an ordinary lampholder.  However it is not impossible that this is connected to detect changes in the supply voltage and thereby regulate the brightness.

On this point, it is worth noting that you can’t adjust the brightness of an LED by altering the driver voltage.  The diode will only conduct (light up) when the input voltage reaches the internal voltage drop of the diode.  If you try to turn the voltage higher, the voltage will remain at the internal voltage drop, but the current will increase and the LED will be brighter.  But if you increase the current too much the LED will overheat and burn out.  The usual way of controlling the brightness is to pulse the LED on and off.  If this is done at a high frequency, the light will appear less bright and the flicker will not be perceived. If the pulse rate is too slow, the flicker can become perceptible and cause problems for many people.

So you live and learn.  to be honest, the bulbs were remarkably cheap, so I couldn’t have expected more and it is an interesting learning experience.

240v G4 LEDs

As a footnote, I bought some 240 v LEDs as well.  These just have a ‘capacitive dropper’ to regulate the input voltage and these probably would work with a dimmer.

Light Bulbs

In the old days, buying a light bulb was simple.
• How many Watts?
• Pearl or clear?

There were some special bulbs, such as for projectors and for photography, but these weren’t mainstream and you’d have to go to a specialist supplier to get one.

Bewildering choice

Nowadays, the choice is bewildering, and something I’m having to resolve as I’m refurbishing my house, so I thought it would be useful to summarise some of the considerations.

Incandescent bulbs were progressively phased out in the UK from 2009 to 2014, being initially replaced by ‘compact fluorescent’ or CFL bulbs and subsequently by LED bulbs.

‘Halogen’ incandescent lamps are still permitted but are generally only used where a small light source is needed, such as in projectors, car headlamps and for some decorative uses.  These are most efficient when operated at a low voltage (generally 12 volts) so these need a transformer in domestic use.

LEDs are the norm

It is fair to say that LEDs are now the norm.  They are bright, come on immediately, generate little heat and have a long life.  They are not perfect.  The main disadvantage is that they can give poor colour rendering.  So lets look at this.

Black body radiation
The CIE colour space and black-body colour temperatures

An incandescent bulb radiates light due to the high temperature of the filament.  The radiation [nothing to do with radioactivity]  is close to a ‘black body’ radiation, which is dependent on the temperature of the heated object – in this case the filament.  We are used to seeing things under such illumination, as this is approximately what we see under sunlight (ignoring the effect of atmospheric absorption).  A black body emits light in a continuous spectrum which peaks at a certain frequency (colour) according to its temperature.  The higher the temperature, the bluer the peak of its spectrum. The ‘Colour temperature’  of a lamp means the temperature of a ‘black body’ when heated sufficiently to glow at the same colour that the lamp gives out.  It is usually expressed in ‘degrees Kelvin’ which are 273 degrees more than degrees Celsius – in other words, water freezes at 273 degrees Kelvin.  0 degrees Kelvin is ‘absolute zero’, where an object has no thermal energy.

Colour Temperature

On the colour temperature scale, a bright red glow is 1000 degrees Kelvin.  At 2000 degrees Kelvin, there is a bight orange glow, rising to a bright yellow glow at 3000 degrees, a yellow-white glow at 4000, an almost white glow at 5000 and a pure white glow at 6000.  At 7000, glow is a blue-white and at 8000 it is distinctly blue.  By 10000, we are looking at a bright sky-blue colour.  The colour temperature of a typical incandescent or halogen bulb is about 3200 Kelvin.

How LEDs work

However, LEDs don’t work by heating an object.  They work by ‘exciting’ electrons to vibrate within atoms, which when they fall back to their rest state emit a photon, depending on the material they are made from.  Nowadays, most LEDs emit photons in the blue or near ultraviolet range, but the blue/UV light is absorbed by a phosphor coating that emits visible light in the yellow range of frequencies (which is why the surface of the LED looks yellow when not illuminated).  By adjusting the balance between the blue of the LED and the yellow of the phosphor, the light can look white (often ‘warm white’, or ‘cool white’  but in reality it omits large parts of the spectrum, especially in the red.  This can mean that the colour rendering of LEDs can be very poor, particularly for skin and other surfaces containing a lot of red.  For this reason, lamps are now given a ‘colour rendering index’ (CRI) which indicates how closely the lamp reveals the colours of an object compared with a natural light source.  A CRI of 100 means that the lamp shows colours exactly as they appear under ‘standard’ daylight.  The test is done by looking at special test colour samples under the lamp and under light of the reference ‘colour temperature’ and rating the differences observed.

Colour rendering
Spectrum of different lights

Typical ‘white’ LEDs have a CRI around 83,  which is better than old fluorescent tubes, but far from ideal,  so this information is often omitted in marketing details.  However a CRI above 90 is needed for good colour reproduction.  It is possible to get better colour rendering by using phosphors that emit red, green and blue light.

A warm white LED has a colour temperature of 2700 K, which is considerably more yellow than an incandescent bulb.

A particular difficulty can exist for film and video lighting, because the spectrum of the LED, even with a high CRI, may not match that expected by the colour sensors in the camera.  For this reason, a special colour rendering index has been developed for video use.

Luminous efficiency

In the old days, you knew how bright a 100 w or a 60 w bulb would be.  LEDs need far less power but the amount of light they give out (which is measured in lumens) depends on their design.

The two-colour white LEDs have the best efficiency, around 120 lm/W whilst 3-colour LEDS produce around 70 lm/W, although the amount of power they need also depends on the efficiency of their control circuitry.

By comparison, an incandescent lamp produces about 15 lm/W and a CFL produces 63 lm/W.

This means that to a rough approximation

Incandescent  LED     Lumens
100 W                24 W        1800
75W                    15 W        1000
60W                    11 W           900
40 W                      6 W           400
20 W                      3 W           300

The circuitry inside an LED lamp

There is yet another consideration – can they be dimmed?  This is not primarily anything to do with the light-emitting diode, but the electronic circuitry within the lamp.  All domestic LEDs have control electronics in the base of the lamp, because the LED must be fed with direct current at 2 to 3 volts.  There are a variety of ways of reducing the mains voltage of 240 volts to this low value, but usually by ‘chopping’ the incoming AC mains so that it is only on for part of the cycle.  The chopped mains ‘fills’ a capacitor until it reaches a certain a low voltage, and then stops the current, which then discharges into the LED.  Depending on how this is done, the lamp may not work with a dimmer, which also chops the mains voltage to drive less power into the lamp.  Some lamps can be dimmed, but only with a ‘trailing edge’ dimmer.

The lamp cap/base

There is yet another consideration – the lamp base.  Traditionally, only the ‘bayonet’ cap was used in the UK, but with the influence of Europe, ‘Edison Screw’ fittings have become very common. Both these ‘caps’ are available in different sizes.  It is not part of this article to consider the pros and cons of the two types of fitting. Most of the lamps described above are available in these two ‘caps’.

Bi-pin caps

There are also many types of ‘bi-pin’ fittings which originated for different purposes. G4 is a small bi-pin fitting originally designed for low-voltage halogen lamps.  G9 is a slightly larger fitting used with higher-power bi-pin mains voltage lamps, and G10 is a large bi-pin fitting intended for high-power mains halogen lamps.  However, these have all be re-purposed so care must be taken that your lamp is for the correct voltage as well as the correct cap.

Considerations when choosing

So, when choosing and LED bulb, the main considerations are:

  • the cap/base to fit the lampholder
  • the voltage of the bulb 230/240 volts in the UK, but may be 12 v in fittings with a transformer to replace some halogen bulbs
  • The colour temperature
    • 2700 = warm white, (i.e. yellow)
    • 4000 = natural white (i.e. sunlight)
    • 6000 = cool white (i.e. skylight)
  • Dimmable or not
  • Colour rendering (if you are doing art/design work)
  • Lumens output
The Circuitry

For those interested in the technology, this titchy bulb contains some quite sophisticated electronics.  I have decided to cover this in a separate blog called LEDs – The circuitry

On one side we have what is essentially the input circuitry – the big yellow rectangular blob is a smoothing capacitor and I assume that the small rectangular things form a bridge rectifier.  Together they create a nice smooth 12 v DC input from the 12 v AC that they are supplied with.  This is fed to the circuitry on the other side.  Although I can’t read the designations on the small chip in the middle, it is something like the one shown in the circuit diagram below.  In essence, it is a current/voltage regulator that reduces the 12 volt input to that needed to drive the LEDs.  I am rather inclined to think that this will not work with a dimmer – in fact it does its best to maintain the LED current whatever the input voltage.


Update on Hardware & Software for making demo videos

I said I would update my previous post when I’d made a couple of videos.  Well, I have made four short videos, so here is a follow-up.

I have found OBS studio to be fantastic! I hardly need to say more.  It’s true that it doesn’t come with instructions, but there is plenty of help available on the web and anyone with some familiarity with Windows will soon find the best way of using it.  I set up OBS studio to record mp4 videos as these are quick to edit and easy to upload to YouTube.

I don’t pre-script my videos, although I do think about what I want to show and how I’m going to present the demo – I do a lot of live demos.  However, I’m often a bit hesitant in my speech, having to think how to do something whilst talking about it.  So I cut out the mistakes and dead space using Adobe Premiere Elements, which is very quick with mp4 videos.  I also shorten them all to about 12 minutes, which is probably enough for anyone to absorb in one sitting.

Regarding the microphone, I have decided that I like the £24 KLIM better than the £85 Blue Yeti.  Whilst the Blue Yeti probably has a better frequency response, the KLIM has a power on-off switch which means I can leave it plugged into the computer.  Also it is better at rejecting the fan noise of the computer (I use a powerful tower machine as I do a lot of CAD work and because my present work space is cramped, I can’t escape from the fan noise). It doesn’t pick up too many breathing sounds or desk bumps. And it is smaller and lighter, again important on my cramped desk.  I think the sound is excellent – I don’t have to be too close and I think my voice sounds quite good.

I can recommend this as an excellent and productive combination that will encourage me to make more demo videos.

Fixing Windows Update – manual installation

Updates repeatedly failing

For some months I have been struggling with Windows 10 Updates repeatedly downloading, installing, failing and reverting to the previous version.  This was infuriating, as Windows was slow and would often restart when my back was turned for a few minutes, meaning that I had to wait an hour or more before I could use the computer again.

There is no indication why it was failing. I’d been running Windows 10 since it first came out, upgrading from Windows 7.  Stupidly, when I first installed Windows 10, I decided to install the ‘N’ version, which excludes the media feature pack.  I had to add this later in order to get USB connections to cameras and other image-related functions to work correctly.  Of course after years of installing various software, hardware and peripherals, it is possible that a library somewhere had been corrupted.

Google came up with many suggestions, but either they didn’t work (like running various checking programs) or they seemed either too obvious and trivial or too complex and risky. The most sensible suggestion seemed to be to go for a complete reinstall of Windows, but I was wary in case I would then need to spend days restoring my setup and apps.  But fortunately it is very simple to reinstall Windows  without losing your current files and apps, so I am putting this here to help others in the same position.

The solution

Firstly, download and install Microsoft’s Media Creation Tool from the following link:

When it has downloaded, choose
Upgrade Now.

You can choose to keep all your files and apps.  It is probably no slower than a Windows Update, but it certainly seems to have fixed my update problem  I’m now running the November 2019 version 1909 of Windows 10 and so far it is looking good.  My PC seems to have all the files and apps (although I had backed everything up first, of course).

You can use the same tool to download the ISO (i.e. a disk image) or create bootable media so you only need to do it once, and have the bootable media for repairs or possible Clean Install.

Note that this is a full and complete new copy, rather than the patched-up version created by Windows update.  Given the repeated update failure, I felt that I should keep an eye out for problems with device drivers.  Windows proudly installs device drivers for almost every conceivable peripheral.  This is an amazing achievement, but sometimes the drivers are not optimal for certain devices, for example failing to initialise special features of a scanner, and you may have to use the manufacturer’s device installation tool to restore their own device drivers.

Have I had any problems?

One thing I have noticed is that some of the Outlook folders have become unindexed and a couple of sub-folders in my inbox seem empty, so perhaps Windows has moved these to a new location.  It’s not a massive problem but I will need to deal with it.

Window Media Pack

Videos not playing

I noticed that videos on the BBC website would no longer play.  I’m not entirely surprised as it’s likely that media feature pack (which is excluded from the N versions of Windows that I have installed) would be updated at some point, and it seems quite possible that this was causing my problems with the Windows update.

Note that if you look up ‘media feature pack’ on the Microsoft Website, you will be told how to download the media feature pack for each new version of Windows 10N except the latest release, 1909 (November 2019).  What gives?

A new feature in Windows Settings
Further probing revealed that there is an important new feature available under the Windows 10 Settings menu, but it is hardly in an obvious place.  This allows you to add many features to Windows, including the Media Pack.

Open Settings, and go to Apps.
Under Apps and Features, select Optional Features

Click Add a feature, and from the drop-down select Windows Media Player

This will now download and install, but to complete the installation, you have to restart your computer.  It will then churn for a while and after that, the new Media feature will be installed.  Very neat!  Website videos now play again.

There are quite a few other useful-looking features for those who want to dabble.


They’re tracking you!

A year ago I mentioned how the ‘General Data Protection Regulation’ had somewhat backfired – now every website want you to agree to its ‘Privacy Policy’, which is of course ‘Newspeak’ (see George Orwell’s prophetic book ‘1984’, where Newspeak is a language designed to control the way we are allowed to think) for permitting them to intrude into our most private moments.

No-one ever reads privacy policies – they are designed to be impenetrable.  But if a privacy policy doesn’t fit onto a single page, you can be pretty sure that it is giving them all sorts of rights over your private information.

What should you do about it?  One of the most intrusive elements is the ‘tracking cookie’.  This can record pretty much anything that you have done on a website, even when you’re not specifically logged in.  If you put in health questions, this can be recorded.  Then other website, such as one selling health products, can look at this and target you with advertising.

There are various apps that let you delete tracking cookies, and I consider that this is an essential housekeeping operation that everyone should do frequently.

I’m rather annoyed with eBay right now.  Although I always buy from a local shop if I can, I needed something that I couldn’t find in after trawling round the local shops.  I do sometimes use eBay and there was a product already in my list that I’d eventually got somewhere else.  So when I selected the product that I actually wanted, to my despair I saw that instead it had placed an order for the earlier product instead!  I realised that eBay had automatically logged me in and when I went to the order screen, it whacked out that order.  OK so I was not careful enough, but I am pretty careful, and if it happened to me, it happened to lots of others.  Clearly a trick to catch people who are hesitating about placing an order!

To be fair, I was able to cancel the order quite easily, but it was still rather annoying, and clearly a deliberate design ‘feature’ by eBay.

I’ve noticed that ‘Google’ is particularly bad at offering a ‘connected’ experience, which is a Newspeak word for ensnaring you in their net.

Broadband connections

Getting temporary broadband
BT cocks up my order

I needed to temporarily relocate my office for a few months.  I need fast broadband and a ‘landline’ telephone.  I already have this in my present office, provided by BT.  My clients must not be affected by this move in any way, shape or form.  The obvious thing is to ask if BT would transfer my contract to my temporary location, and move it back when my office has been refurbished.

‘Yes’, they say, ‘No problem, and we won’t charge you.’  That’s fantastic.  The new location is only a short distance away.  ‘Sorry, Sir, that is on a different exchange.  We will have to give you a new phone number’.  ‘OK, no problem, it’s only for a couple of months.’ ‘Sorry, Sir, but when you move back, we will have to give you another new number, because we only hold them for 60 days!’

‘Oh, sugar! I exclaim, ‘So to keep my number, I need to take out a new contract and redirect my old number to the new one?’

‘Yes, that’s right.  And the minimum term for the new contract is only 12 months!’

I can’t waste time on this, so through gritted teeth, I say, ‘OK, sign me up to the new contract’.  The firm will pay and it’s one of the costs of refurbishment.

After a few days, I haven’t heard anything from them, so I ring up again.

‘Sorry Sir, but we have no record of any order from you! However, if it is only for a few months, have you considered mobile broadband?  Go into an EE shop and ask them!’

EE Mobile broadband

Well, I know that EE was bought by BT, but even so this was quite unexpected.  Off I went to the EE shop and bought a 4G Broadband Router with 100 GB of data per month for £35 per month.  Minimum term 2 months, plus £100 up front for the router.  This is very competitive with fixed-line broadband and I have to say that I’m entirely delighted with it.  I’m getting about 10 MB/s download and about 3 MB/s upload, but my router is located on a window-sill in a weak-signal part of the building.  Even so, it is fast enough to stream TV and to do normal office work.  I can get a strong signal in another location, and the data rate is faster, but it isn’t convenient for me to use that location.  I could have an external aerial, but it isn’t necessary.

Update on EE mobile connection quality

I have found that at certain times, the 4G signal can drop out. This is very irritating when streaming a film, as it seems to upset my streaming device. I’ve relocated my EE box but it hasn’t eliminated the problem entirely.  Although the authorities can find out which mast you are connected to, the public can’t do this, presumably for security reasons. I presumably the data signal drops when the network is saturated, and this  happens when everyone wants to use it!

Keeping your landline number

EE even said that if I hadn’t been in contract with BT, I could have transferred my landline number to EE and then it would have been portable.  I’m not 100 % sure about this, but I have kept my landline number for mainly sentimental reasons, as I use VOIP for business calls, which is working well with the router.

One thing I particularly dislike about BT is that they keep changing the name of the package, but this isn’t shown on the bill, nor is the contract termination date.  Indeed, whilst I got sales calls from them at the contract termination date, none of them said that my contract was coming to an end.  They simply tried (and succeeded) to inveigle me into a new contract.

Just as I moved to my new location, I got an email on my mobile from saying that Royal Mail had a parcel for me from BT.  Obviously a scam email coming from an address like that.  Then in the entrance lobby, I saw a package addressed to me from BT.  It was clearly a home hub.  They had spelt my name wrongly, though.  Yes, the twerps had actually placed an order from me, but owing to the incorrect spelling, I never received the confirmatory email (and I never will)  which also explains why they couldn’t find my order.  Needless to say, I have cancelled it.  I asked whether the email to my incorrect address had bounced, but they said they don’t check! Shriek! Scream!! What a way to run a business!!!

BT’s new website

When writing this post, I thought I’d check the BT website and I saw that everything has changed without warning. They have replaced their ‘connected world’ logo with a boring BT in a circle and they have changed the names of everything again.   For new contracts, landline UK phone calls are now at a flat rate of 20 p a minute on top of the line rental charge of £20 a month, but you can now buy a package of calls – 500 minutes is £5 a month extra (the cost of 25 minutes ‘pay as you go’.)  This is not cheap, but I think much more sensible than all the pesky ‘add-ons’ which put the prices up too much.

However, if you want unlimited everything, including landline and mobile calls and fast broadband, this will set you back an eye-watering £85 a month on a 24-month contract!!  That is expensive, although maybe I could have got an unlimited data sim and an unlocked 4G router.

Anyway, I absolutely HATE their new website.  They haven’t fixed all the links, so unless you go into it from a particular direction, it’s entirely sales orientated and you inevitably end up on the ordering page, even though you are trying to find information.  All these daft names, yet I can’t find basic information about my contract.

Bottom line – 4G mobile broadband seems to be the way to go, especially as an upgrade to 5G is already coming down the street.