More goings on

Up early, off for a walk, collected some more stones, returned home a couple of hours later and had a late breakfast. It was Thursday. It began well enough, bright and sunny but the clouds began to drift in and drop their load of rain. It got colder as forecast but it wasn’t too bad. E went to do the weekly shopping before noon, the second time in two weeks. She traditionally goes shopping in the afternoon but I fancy she has decided earlier is better. I think it is too as it leaves the rest of the day for her to do other things. I could go shopping with her but as she takes along her mom my presence wouldn’t be appreciated, I would spoil their routine. As it happens I don’t much like shopping for food so it suits me fine to stay away. I was able to concentrate on my little project. Having collected the necessary components I needed to build the interface unit for controlling the light in the garage I discovered I had a more suitable relay for the job. Initially I thought I had only one which operates on a 12 volt DC (direct current) supply which necessitates the use of a rectifier but I found I had one that operates on a 12 volt AC supply so I didn’t require the rectifier. This made the task far easier as I only required two components in the unit……

You can see the relay on the left inside the box and the transformer to the right. I rigged it up for testing by plugging it into a wall socket as it will be done when installed in the garage. I connected the reed switch (shown lying on the lid) in order to test the circuit. As the magnet was brought close to the reed switch the relay was activated. The integral switch in the relay will be used to switch on the light. The whole unit will only power up when the outside photo cell senses it is dark. The next phase is to install the wiring to the photo cell. Next I have to fix the reed switch in such a position to allow an existing magnet on the door to operate it when the door is opened and to install the wiring to the switch itself. Finally I have to purchase an LED floodlight then install the wiring to the control unit. As time permits I will get those things done.

Shirley Anne

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Goings on

I wrote yesterday about our neighbour’s panic attack after she had discovered her dog had died. She doesn’t enjoy good health and is reliant upon her oxygen bottles else struggles to breathe some of the time. E and I were concerned that she was over-stressed but she finally calmed down whilst we were there. Today, Wednesday I called in to see her after I had earlier phoned to see if she was alright. Thankfully she had settled down and was her usual self. I had been exercising on the gym equipment soon after getting out of bed but at that time it was too early to call next door to check upon her. After my breakfast late in the morning I decided to sort out what pieces of electrical equipment I had in stock with which to build the circuit for the garage light project I have been mentioning in previous posts. Finally I was able to gather enough bits and bobs to make progress…..It always seems the way when searching for the right parts I have some of them but not all of them. I then find I have other suitable parts but not all of them are usable with the first lot. An example would be a reed switch which is only suitable in low-voltage situations., as here… That means a transformer is required and also a low-voltage relay. A low-voltage relay would use an alternating current and could be used directly with the transformer, if I had a suitable relay. I found I had a low-voltage relay which uses direct current and therefore added to the transformer I needed a rectifier too! Fortunately I did possess all the parts necessary after salvaging them from redundant electrical gear I had. I even found a suitable box in which to install them, see picture above. I left off working on the project as it was by now lunch time and after lunch I had some gardening work to do. First of all I had to sweep up more leaves again and it was then I began to notice montbretia and bluebells here and there in the flowerbeds. Once again I set about digging them out. This is an ongoing task. Most were removed early last year but I always knew there would be more appearing for a time.

Shirley Anne

Polarity

English: Types of electric current
Types of electric current (Photo credit: Wikipedia)
4 diodes bridge rectifier
4 diodes bridge rectifier (Photo credit: Wikipedia)

If you are an electrician, technician or electrical engineer you will know all about polarity. For those who don’t it is a reference to which way round a circuit is connected to its supply or the way the supply is connected to the circuit or appliance. Most people have an understanding about direct current and alternating current. Typically the current supplied from a battery (of cells) flows in the one direction only whereas the electrical supply to a house (and other places of course) is alternating and essentially flows in both directions, though that is a bit of a theoretical misnomer. Certain things will not work if the current is supplied in the wrong direction, one of those things being diodes. In fact diodes are installed in circuits to ensure current can only flow in the one direction. LED lights or light-emitting diodes are in fact specially constructed diodes which emit photons when a current flows through the device. If the current is presented the wrong way round (wrong polarity) they will not light up. However they can be used if supplied by an alternating current if a bridge rectifier is used.  A bridge rectifier is a device constructed with diodes connected in a special way which forces the current to flow in one direction. Here ends the brief electrical lesson but I write it in order to explain my post.
I had installed an LED strip light (resembling a fluorescent lamp) in a house in summer. The lady called me to explain that it had ceased working so naturally I went to investigate. I discovered that the lamp (tube) was indeed at fault as the supply was intact. The supply to the lamp is at one end only, unlike the fluorescent equivalent which is supplied at both ends. That obviously means the tube itself has to be installed the right way round so that the supply can connect to it. Now then, the lighting unit manufacturer has installed the correct colour-coded internal wiring, brown and blue which are live and neutral respectively together with a small fuse. The lamp connector therefore has one brown and one blue conductor connected to it. The end of the tube lamp which plugs into it is marked L and N denoting which terminal connects to each when the lamp is inserted. However when the lamp is inserted so that it shines down into the room the connections end up the wrong way round! That would mean that the lamp supply is the wrong polarity or the wrong way round but in fact it didn’t matter in this case for the lamp worked whichever way it was inserted. That could only mean that a bridge rectifier was in circuit within the lamp’s electronic components. Why then the need to mark the terminals on the lamp L and N? I can only assume it is for information when connecting it to a direct current supply but even that wouldn’t be correct as for a DC supply they would have been marked with the symbols + and -. So why mark the lamp in the first place? I had the lamp replaced under guarantee and it worked just as the other had done. If only the manufacturer had indicated these things in their literature, it would have saved me the time and effort trying to figure it out for myself. The lamp was replaced under guarantee but my time had to be paid for though.

Shirley Anne

Just when….

LED Lamp with GU10 twist lock fitting, intende...
LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps. (Photo credit: Wikipedia)

I had no real plans on Monday but I did have a small job to attend on. A local guy asked if I could check out the lighting in three upstairs rooms. He had exchanged the small halogen lamps for LED (light emitting diodes) versions exactly like the ones shown on the right and he found that the LED ones remained dimly lit even when the circuits were switched off! Although LED lamps only require around 1.2 volts DC to work there has to be a transforming and rectifying circuit built within them in order to plug them directly into the 230 volt AC supply else they would explode! There were no dimmer switches involved and no driver devices simply an on-off switch by the door. I couldn’t see why the lamps remained dim when the switch was off but assumed that somehow their internal circuitry was holding a charge for a while. Evidently the lamps were remaining dimly lit for hours on end so my theory went out of the window. On removing the fittings from the ceiling however revealed that their connections were not secure and worse than that they were not earthed even though earth wires were present! It seems that ‘some old guy’ had fitted them and couldn’t be bothered to connect the earth wires. In doing so it made all the earth circuit redundant and the next light fitting down the line would not be earthed either. I stripped back the cables and made good the earth connections on all of the fittings whilst reconnecting them to their supplies. I powered up the circuit and tested the lights to make sure they were working and when I switched them off the original problem with the LED’s remaining dimly lit had still not been resolved.  On paper it doesn’t make any sense but funny things can happen with electricity. I could do no more at that stage so and returned home with nothing in mind to do. I decided to practice playing my songs on the guitar and I made five recordings of a new song I’d written the day before and then placed it on my YouTube channel. I don’t know what it is with YouTube but I always seem to have difficulty when I am uploading a video. It took me a couple of hours to record the one song before deciding which version to upload. Now I have 45 of my own songs on there but only this new one features me singing. It has been a long time since I attempted to sing so this first effort might not be my best but I think it is good for a first attempt. Maybe I will re-record some of the others and sing too. Just when I thought I had nothing to do it all changed.

Shirley Anne

PS. I revisited the house the following day (Tuesday) to re-check the light circuit using sensitive meters but found I still couldn’t get a reading to explain the phenomena. I could tell that there was a connection box somewhere in the ceiling by the way the wiring was configured and because the colours were not consistent. I suspect the box may be damp inside or some other fault may be present, however, access to the loft had been removed during building alterations some time ago. The owner of the house plans to re- open up that access so until then I am unable to see if my suspicions are correct. He wants me to return to make alterations to his supply board soon so I should be able to check it out then.