Wednesday, 8 April 2015

Electronic Transistor / Diode / Resistor / etc. Tester

I always manage to end up with a few transistors which have lost their markings or lost the pin out data for those which are labelled. Looking on eBay at the bare bones electronic testers with graphic display from China I finally decided to invest £15.99 including shipping. It finally arrived today, well wrapped in layers of bubble wrap and all ready to attach a 9V battery. (not provided) There are no instructions with it but most things are very easy to work out.


Lift the lever of the ZIF (zero insertion force) socket, put a transistor in three holes, push the lever back down to clamp the leads and press the red Test button.  Make sure the transistor goes in holes marked 1, 2 & 3. Any set will do.


First the display shows the battery voltage and says it is testing.


Then once it has worked out which way round the transistor is and what type it is the display changes to show that information, along with gain and a couple of other parameters I haven't sussed out yet. It won't give a transistor number but knowing which type it is and which pin is which is a great boon. Better than a pile of unidentified transistors.



It will also test resistors:


diodes, including LEDs:


and also capacitors, which I haven't tried as yet.  The listings stress that capacitors must be discharged before testing otherwise the tester could be damaged.  On this quick test of  it I am impressed, well satisfied with the investment and will find it very useful around the shack.


  1. I have a similar thing on my multimeter but I have to know which way round to put the transistor. I am playing with a Fiat ECU at the moment as mine is a bit dodgy. It could do with a diode dropping in between the fuel solenoid and the ECU as I'm pretty sure current is leaking the wrong way.
    This looks a very reasonable bit of equipment. I hate discharging capacitors. I used to pop a big resistor across them but having set fire to my fingers will now either leave them alone or get one of those proper sink things from Maplin.

    1. Adrian: I have that on my multimeter as well but never use it.
      I used to use a hefty screwdriver for discharging. Not the best way but great when in a hurry to get rid of several thousand volts. (In the far off days when I used to tinker with, and build, TVs using ex war dept radar tubes.)

    2. PS. I now get all my batteries from Maplin. They are just perfect and cheap.
      I had a Canon strobe tube go and a new tube is a tenner and a bit of fiddling The capacitor set fire to a big resistor. The repair was great and I am still using the strobe. Burnt fingers was my fault.