How to check a resistor – an ohmmeter. What about a diode? Multimeter. What about the capacitor? capacitive meter. And the transistor… But isn’t it easier to buy one device that will check the performance and basic parameters of LEDs, diodes, capacitors, transistors, resistors and other radio elements. In general, it’s time to buy such a transistor tester on Aliexpress , especially since its price is less than $ 30. The impetus was the repair of the automatic washing machine , where in order to check the electrolytes, I had to run to a familiar radio amateur. He also noticed such a device, immediately kindled with sympathy for him (to the device, of course).

On the Chinese site there were 5 main models from the inexpensive price segment. I decided to buy the best of the worst – T7 transistor tester . It is favorably distinguished by the presence of a case (many of them remain frameless), a lithium battery instead of a 9V Krona and a beautiful color display. There is also the possibility of decoding the IR signal, so the device came out full of smartos!

CHARACTERISTICS OF THE T7 TESTER

• Automatic detection of NPN and PNP transistors, n-channel and p-channel MOSFET, diode (including dual diode), thyristor, transistor, resistor, capacitor and other components.
• Automatic component test and LCD display
• Can detect MOSFET protection diode, gain, transistor pin detection
• MOSFET capacitance measurement, threshold voltage
• One button operation, automatic shutdown.
• Only 20 nA of current when turned off.
• Automatic identification of components by foot position.
• Bipolar transistor measurements – gain and base-emitter threshold voltage.
• Identification of Darlington transistors.
• Can measure two resistors at the same time, so you can measure the potentiometer.
• Resistance measurement with a resolution of 0.1 ohm, up to 50 MΩ can be measured.
• Can measure capacitance 30pF – 100mf, resolution 1pF.
• Measure equivalent series resistance ESR, 0.01 ohm resolution.
• Can show the forward voltage drop across the diode.
• LED defines as a forward voltage drop across the diode
• Can measure diode capacitance. If a bipolar transistor, it will also show the through capacitance.
• Powered by 1000 mAh lithium battery
• Price 25-30$

EQUIPMENT

The kit includes probes on wires that can be used to measure parts without inserting into the socket. And even a couple of test parts the seller did not regret putting in the box (+ a red LED and a 10 microfarad capacitor with a 200 Ohm resistor to my stocks).

WORKING WITH THE DEVICE

There is only one button – insert the part and click “Test”. When turned on, it displays the battery charge status for a couple of seconds, after which it starts testing. The result is highlighted on a black background with colored symbols – beautiful! Below are the test results for various parts.

DISASSEMBLY

Of course I decided to look under the lid. Inside is the same familiar board as in the younger models. I suspect that all the difference lies in the firmware and catering. Well, okay.

SCHEME

The basis of this transistor digital tester is the AtMega-328 microcontroller. Here is an approximate diagram, plus enter an amendment for the battery charge module and the 3.7> 9 volt converter. It is charged from Micro-USB. For the convenience of monitoring the process, a small LED is displayed near the socket. Bicolor.

CONCLUSIONS ABOUT THE T7 TESTER

Pros – only pros! The plastic case is of high quality and convenient, the LCD screen is clear and bright, the battery power lasts a long time (enough for 100 measurements), universal, inexpensive (at least 1,500 rubles is normal for me), external probes are available. In general, take it – you will not regret it!