Showing posts with label zener. Show all posts
Showing posts with label zener. Show all posts
Friday, October 24, 2014
Simple Zener Tester Schematic
The circuit can be simply Q1 is connected as a current source. By D1, there is a constant voltage on the base, and it is worth considering the selected resistor in the emitter approximately 5.6 V. With an emitter resistor of 5K6 R2 will then 1mA through the transistor.
With the chosen resistors in the circuit the current is approximately: 1mA, 2mA, 5mA, 10mA and 20mA. Great precision is not required.
If meter is chosen here for a small DVM module. However, every other meter is applicable, provided that the input resistance is high enough.
Construction:
The circuit is simple to build on a piece of PCB holes. Note that the DVM module separate from the circuit galvanic isolated power supply needs.
Using
Connect the test zener diode between the terminal A and K. Start with a current of 2mA. This is a safe value for most type zener diodes. Depending on the type of zener diode, may be chosen for a greater current. Than the Zener voltage will vary slightly.
Join the zener diode on backwards, the meter will indicate approximately 0.7V. The same picture shows an ordinary silicon diode. A germanium diode, a voltage of about 0.3 V to 0.4 V indicate when a Schottky approximately 0.2 V indicates.
Connect an LED to A and K, it will be highlighted and the Vforward (LED voltage) of the LED indicate.
The diode / LED failure, the meter displays zero if the voltage at the collector of Q1 is, this is> 25V.
parts List
Bridge rectifier BR1 = 40V 500mA
R1 = 3k3 ¼ W
R2 = 5K6 ¼ W
R3 = 2k7 ¼ W
R4 = 1k ¼ W
R5 = 560 ohm W ½
R6 = 270 ohm ½ W
C1 = 470µF 35V
D1 = 6V2 zener 400mW
Q1 = BC161-16
S1 = on / off switch
S2 = 5 modes 1 mom ignition switch
ENG = The diode under test (Device Under Test)
DVM DVM = module of BACO or Dick Best (input adapted to 200V)
Wednesday, December 11, 2013
Voltage Rating Tester for Zener Diode
I have teamed up with Magazine Mikro Elektronica for this project. Please visit their site. I am very grateful to Aleksandar Dakic for the kind translation into Serbian and Romanian languages.
Voltage Rating Tester for Zener Diode Circuit Diagram
Notes:
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 555 timer 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 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.
Voltage Rating Tester for Zener Diode Circuit Diagram
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 555 timer 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 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.
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