Zener Diode Testers

Posted on Feb 5, 2014

Using a single 555 Timer IC and a small transformer to generate a high voltage, this circuit will test zener diodes of voltage ratings up to 50VDC. The 555timer is used in the astable mode, the output at pin3 drives a small audio transformer such as the LT700. This has a primary impedance of 1K and a secondary impedance of 8 ohms. Used in reverse the unloaded ac voltage is around 120volts ac. This is rectified

Zener Diode Testers
Click here to download the full size of the above Circuit.

by the 1N4004 diode and smoothed by the 2. 2u capacitor which MUST be rated at 150 VDC. The zener under test is measured with a multimeter set to DC volts as shown. The load current switch enables the zener to be tested at 1 or 2mA DC. The rectified DC load, but a good zener should maintain the reading on the volt meter.

Leave Comment

characters left:

New Circuits



Popular Circuits

Tin Can Waveguide WiFi Antenna
800W high power mosfet amplifier Schematic Diagram
convert square wave inverters to sine wave inverter
op amp Humming and Transmission issues
tone control circuit designed
Arduino UNO Tutorial NightLight
INA321 322 input current protection circuit diagram
ISO103 gain adjustment circuit diagram
Novel multifunctional high-power amplifier module 01