Testing Components

Testing Components

Wireless mains voltage tester.

Description. This circuit can be used to test whether mains voltage is present or not without having electric contact with mains line. The CMOS IC CD4033 is the heart of this circuit. The CD4033 consists of a 5 stage decade Johnson counter and an output decoder for converting the Johnson code to a 7 segment […]

Testing Components

How to test FET’s-Jfet and Mosfet

All the testing methods below uses a multimeter and hence its How to test FET’s especially the JFET and MOSFET using a multimeter. How to test an FET ? FETs are checked by measuring different resistances by a multimeter. When resistance is checked between source and drain, it should be of the order of 10

Testing Components

How to test a thermistor

Thermistors are of two types, NTC (negative temperature coefficient) and PTC (positive temperature coefficient types). As their name indicates the resistance of an NTC thermistor will decrease with temperature and the resistance of a PTC thermistor will increase with temperature. Both PTC as well as NTC thermistors can be roughly checked by using an analogue

Testing Components

How to test a capacitor.

This article shows you how to test a capacitor using analogue multimeter. Firstly short the capacitor leads for discharging it completely. Set the multimeter to high resistance mode. Connect the multimeter terminals to the capacitor leads. For electrolytic capacitors the positive terminal of multimeter must be connected to the positive lead of the capacitor and

Testing Components

How to test an LDR

LDR (light dependent resistance) can be very easily tested by using a digital multimeter. We all know that the resistance of an LDR varies according to the light falling on it. At bright light, the LDR resistance will be around 500Ohms and at darkness the resistance will be around 200K. For a proper diagnosis we

Testing Components

Testing a UJT

UJT (Uni junction transistor) can be easily tested by using a digital multimeter.The three steps for testing the health of a UJT are as follows. 1. Measuring the resistance between B1 and B2 terminals. Set your digital multimeter in resistance mode.Connect the positive lead of multimeter to the B1 terminal and negative lead to the

Testing Components

How to test an SCR

Testing SCR using a multimeter. A multimeter can be used to test SCRs quite effectively. The first procedure is to check the diode action between the gate and cathode terminals of the SCR. This test is just like what you have done in the case of testing a silicon diode (see testing a silicon diode).

Testing Components

How to test a triac.

Testing triac using a multimeter. A multimeter can be used to test the health of a triac. First put the multimeter selector switch in a high resistance mode (say 100K), then connect the positive lead of multimeter to the MT1 terminal of triac and negative lead to the MT2 terminal of triac (there is no

Testing Components

How to test a diode

Diodes are one of the components that can be tested very easily.Ordinary diodes as wells as Zener diodes can be checked by using a multimeter. While testing a diode the forward conducting mode and reverse blocking mode has to be tested separately. Testing ordinary diode using a digital multimeter. To check an ordinary silicon diode

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