Saturday, 10 January 2015

Versatile component tester for under a tenner!

Not too long ago, if you wanted to accurately measure your resistors and test your transistors, you bought a multimeter for about £20, but if you wanted to have something that automatically identified the transistor type, told you its pin out, and its beta, you needed a tester that cost near a hundred pounds. Add to that if you wanted to measure the equivalent series resistance of your capacitors, that was another £50 or so for a ESR meter, and if you wanted to measure inductance without messing about with noise bridges and tuned circuits, probably another few hundred!

This week, after only 8 days in a container from China, and for a fraction under £8 all in, I took delivery of a ATmega microcontroller based component tester. These are available in various forms, various connections, and as ready built modules or kits. I bought mine ready built, off ebay.

Most of the electronics are under the LCD, which is very well backlit. There is a contrast control preset at the top of the board. The module can be supplied either by a PP3 battery or an external supply. Ive been using a PP3 as I happened to have one handy. This version has screw terminals for the test connections which are a bit awkward, so i'll be adding test clips later. Initially it did some odd readings on inductance. I later found out that there is a calibration method using a three way shorting link. Once this is done, it reads quite accurately, certainly enough for most jobs, although there is a 35pF offset on the capacitance readings which is a bit annoying for dealing with small values, and its lower limit on inductance is 10uH, a bit too high for a lot of radio work.

Heres it measuring an unknown vintage Germanium transistor, just look at that atrocious Beta!

 It might not be the worlds most precise, its capacitance and inductance ranges might not be as wide as would be liked, but for under a tenner, all in, it does all this -

Capacitance & ESR
Inductance & series resistance
Diode polarity, capacitance and forward voltage
Transistor type, pinout, beta and base/gate forward bias

1 comment:

Leandro Silva said...

Could you show me the site you bought it?