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Voltage Rating Tester for Zener Diode

Tue, 07/28/2009 - 09:42 — vip

Overview

The circuit has been constructed to test and measure the voltage rating of zener diodes.


Zener Diode Tester Circuit Diagram

Mon, 07/27/2009 - 13:02 — vip

Here is a handy zener diode tester which tests zener diodes with breakdown voltages extending up to 120 volts. The main advantage of this circuit is that it works with a voltage as low as 6V DC and consumes less than 8 mA current. The circuit can be fitted in a 9V battery box. Two-third of the box may be used for four 1.5V batteries and the remaining one-third is sufficient for accommodating this circuit.


Connection Tester

Thu, 07/23/2009 - 15:30 — vip

Description:
A low resistance ( 0.25 - 4 ohm) continuity tester for checking soldered joints and connections.


Beeper to find short circuits

Thu, 07/23/2009 - 15:26 — vip

This circuit uses two 741s or equivalent op amp to form a beeper that is used to detect short circuits. This design offers a way to trace resistance in the milliohm range, right to a short between bridged traces beneath a solder mask. A1 is configured as a multivibrator. R1 and C1 determine the frequency of oscillation and Q1 and Q2 boost the output. Assuming a virtual ground at the output of A2, free-run frequency is about 1kHz. Q1 and Q2 deliver a +/-10v squarewave to R4, dumping a +/-100mA through a short circuit placed across the probe tips.


IR Remote Control Tester

Thu, 07/23/2009 - 15:10 — vip

Notes: As I was developing my IR Extender Circuit, I needed to find a way of measuring the relative intensities of different Infra red light sources. This circuit is the result of my research. I have used a photodiode, SFH2030 as an infra red sensor. A MOSFET opamp, CA3140 is used in the differential mode to amplify the pulses of current from the photodiode. LED1 is an ordinary coloured led which will light when IR radiation is being received. The output of the opamp, pin 6 may be connected to a multimeter set to read DC volts.


Crystal Tester

Thu, 07/23/2009 - 14:54 — vip

This circuit enables you to test quartz resonators at the range values from 32kHz to 24MHz. Confirmation of good state of quartz resonator is done by diode signalling LED and acoustic signal. Switch S2 enables change of range .

Circuit diagram

Crystal Tester


Transistor Tester

Thu, 07/23/2009 - 14:49 — vip

This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits.


Zener Diode Tester

Thu, 07/23/2009 - 10:03 — vip

 

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.

Circuit diagram

 

Zener Diode Tester


Mosfet TESTER

Thu, 07/23/2009 - 10:00 — vip

This is a variation on the astable multivibrator. Circuit was recently developed to test for N-mosfets(the power kind e.g irf830)
I don’t claim circuit can test all bad mosfets or all fault mosfet conditions. If mosfet is working it will operate in the astable multivibrator circuit causing the Led to flash.
A bad mosfet will not cause the LED to flash.
Below is the circuit diagram, the other half of the astable utilizes an npn transistor to make the circuit cheap.
Almost any npn transistor will work in this circuit.


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