Tchaibo Watt-o-meter only reads 218 volts

I have this one. Works well. I'd recommend the backlit version for 20 quid.

Does you Tchaibo have an internal battery? If so is it running close to being flat and needs replacing?

I haven't had any problems with the type which Maplin used to sell, I think it was a re-badged ProDIGIT 2000MU-UK (aka 2000MU-01)

There are two 357/303 button cells but they only maintain settings and stored data. It works fine without them and reads 218V with or without them.

My desktop pc and all its related stuff is powered through it and I am primarily interested in the Watts display but if the mains voltage is under-reading significantly, how do I trust the power consumption ?.

well 218V rms is within spec. Maybv the waveform is odd.

If the rms is calculated correctly the waveform form factor is irrelevant.

IF.

How many meters just adjust a rectified average?

Well power meters certainly should not, particularly when they also calculate the reactive power.

Ah. The political Left's favourite word.

Should.

Slightly ahead of 'ought'.

I think I will take my weary cynicism to an early night and watch fantasy movies on the laptop.

See if you can get a part number off the main chip.

If it uses the modern design, the meter is very similar to a smart meter. Two sigma-delta converters running at

It's capable of measuring lower power factors quite well. Your regular multimeters cannot make a lot of sense out of the mains idle power (+5VSB portion) of an ATX supply. The Kill-O-Watt designs can determine that the W and VA are quite different values at idle.

When measuring an incandescent light bulb, the PF should be close to 1.0 . The light bulb power is double when the lamp is cold, but in a few seconds it should settle to the nominal value.

There are a few checks you can do like this, to determine whether it is a modern design, or it is... something else.

Paul

I bought it over 20 years ago when Tchibo (Tchaibo?) had high street shops in the UK. Also branded TCM I think.

QED Not a modern design and I think the mains voltage value on display has slowly dropped on the last 10 years or so.

I'll just get a 'modern' one.

The only time I heard of them was when they seemed to occupy a few feet of shelf-space within Sainsburys.

There was one in Romford for a few years. A really odd shop, impossible to categorise.

Indeed. I have a still working printing calculator from them. I used shops at Wimbledon & Woking. Also, I have a mains powered small chain saw on an extendable pole..

Indeed, that sort of sums up the layout of the one that was in Swan Walk, Horsham.

That's where I bought mine about 20 years ago. I just checked and it still works. In fact, as I was looking it moved from 239 to 240V. As you noted earlier it's marked TCM on the front. I've also still got one of their weather stations bought around the same time. The external thermometer/hygrometer expired a few years ago, but until then it worked well (around 15 metres from the base station). I'm still using the base station.

I have a Brennenstuhl one which seemed to be very inaccurate. It also takes a couple of button cells for saving values over power loss, which I didn't fit. However, I then discovered that with the batteries fitted, the readings were now correct.

I have 3 of those, bought from Maplin many years ago.

They aren't working as well as they did. They're taking a noticable 1 or

I haven't got around to looking inside, but maybe a capacitor or two has gone out of spec?

I've got two of them. Set one to Watts and it reads zero. Plug in a load then unplug the load - and it won't return to zero. Crazy.