Thursday 3 March 2011

Simple Zener Tester

zener tester

2 comments:

  1. the zener test diagra is wrong as that will not work , as the 15k should be from posative to the base of the transistor and the test diode from base to negative ?

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  2. Yes, it is missing a connection between the junction of zener and 15k resistor to the base of the transistor. It is incredible how people publish things without verifying what they are posting. Also, there is no reason whatsoever to use a 1A fuse at primary with a 200mA fuse at secondary where the current would be higher, it makes no sense. Also, the circuit total current would be only through the 15k resistor and the voltmeter what is ridiculous low, the 1000 µF is overkill, any 47 µF would be more than enough to filter 60Hz ripple for such low current. The 47µF at the base could even be a 1µF capacitor, if you really want one there. This circuit may be okay to test zeners, but the designer didn't know very much about electronic projects. I understand when people just grab surplus componentes from the drawer and built something. Sorry.

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