How To Easily Build Your Own FET Tester

Myads

There is no doubt that nowadays we are seeing more FETs being used in the electronic equipment. FETs can be found in the power section, LCD inverter, UPS, Amplifier, Monitor B+ and S-correction circuit, ATX power supplies and etc. When this component fails, one has to use a meter to test it to check if it is good, shorted, open or leaky. The meters can be a normal multimeter, specialize FET tester like the Peak Atlas Tester, Sencore Cricket Tester, B & K transistor tester and etc. The specialize testers are expensive and most of it could helps you to automatically identify the pins of the FET (gate, drain or source). If you use a normal multimeter, you have to identify the pins on your own. Assuming if you do not know the pin out of the FET, you can always check from the data book or even from the internet. If you want more information about FETs, you can click HERE to visit Wikipedia website. 

Typical example of specialize transistor tester

Okay, this month newsletter is about building your own FET tester and this article was contributed by Mr Behzad.

 

FET Tester Schematic Diagram

This is a simple and easy to build FET tester. It can test N-CHANNEL and P-CHANNEL FET.  These are the following components that you need:

1) 2 pcs of red color LED

2) 1pc of green color LED

3) 1pc of DPDT switch (DPDT stands for Double Pole, Double Throw)

4) 1 pc of On/off switch

5) 1 potentiometer 10k ohms

6) 2pcs of resistor 470 ohms 1/4 watt

7) 1pc of resistor 470 K ohms 1/4 watt

8) 2 IC sockets- 8 pins dip

9) 1 small pc of project/circuit board

10) 1 pc of knob for the potentiometer

11) 1 Project box

12) 1 pc of 9 volt battery

13) 1 pc of 9 volt battery holder/connector

The IC sockets are good for holding the FET during testing time. We use just three pins of each socket for the Gate (G), Drain (D) and Source (S). One socket is for N-CHANNEL FET and the other one for P-CHANNEL FET. The DPDT switch is good for changing the mode of tester from testing N to P-CHANNEL FET. Another advantage of this tester is that if you have been using multimeter to test on FETs, you will find that our hands is too big for the small FET pins (TO- 92 Case). Thus by inserting the small FETs into the IC socket, you will eliminate the error of one finger touching on another pin during testing time using the multimeter.

Test Result

If the FET is shorted one of the red LED will lit.  In order to confirm that the FET under test is good even if you increase the potentiometer to maximum the red LED should not lit otherwise the FET is bad or leaky. For a good FET the green LED will light up.

Thank you

Behzad

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Conclusion- According to Behzad, the meter was easy to build and the cost was very cheap too. If you have the time, try build one and see how useful this tester is. This tester diagram was provided by Zed Pato and Mr Behzad from Iran who had assembled it. Zed Pato is from the Philippines and he is a electronic repairer and you could visit his blog by clicking HERE.

Introduction To Electronic Servicing

Myads

Introduction To Electronic Servicing

With countless new electronic products or equipment reaching the market, there is a large demand for electronic repair technicians and engineers. As a result, you may be interested in moving into the electronics repair field. The electronic servicing field is considered a prestigious job. If you are really good in your work, there is almost no competition and you can acquire skills that allow you to earn enough money. Servicing is an ideal combination of your intelligence, efficiency and easy mechanical work. By gaining more experiences the efficiency and skills automatically becomes instinctive.

Many electronic equipment servicing operations are simpler than you may think. You will be surprised to learn that most servicing problems have simple causes – worn cables, dirty connectors, a loose screw in the works, and so on. Almost any end-user can check for this kind of problem. However, there may be other problems caused by component failure. You may give up and say “I’m not an expert in electronics”. You may be surprised to learn that many “troubleshooting” jobs do not require much detailed knowledge of electronics. Even in a “professional” troubleshooting operation, the technician or engineer may not have a detailed knowledge of the circuitry. Electronic servicing is not mysterious or difficult; it only requires your patience and some basic knowledge in electronics.

 

If you are thinking of becoming an electronics repair technician or engineer, you need proper qualifications. Get at least a certificate in basic electronics or its equivalent through electronic courses. You can go far beyond this by continuing up to a diploma level. As you progress, you will discover your weakness. It’s then up to you to find out more by attending professional courses or reading up related books. Of course, the higher the level you desire, the better. Electronic equipment breaks down every second and we will need good technicians and engineers to ensure a good repairing job is done. So, if you are thinking of joining us – go for it!!!