We assemble a 150 volt LED tester from improvised parts. A simple scheme. Compact tester. скачать в хорошем качестве

We assemble a 150 volt LED tester from improvised parts. A simple scheme. Compact tester.

LED tester, from improvised means. We check the LEDs and other elements. We will need a transformer, a transistor, a diode and two resistors. All parts can be taken from non-working devices, or purchased. Also, wind the transformer yourself. I used a transformer with a broken LED driver, you can take a transformer from charging your phone. the transformer winding with a lower resistance is connected to the base of the transistor through a 20 kilohm resistor. The winding with high resistance is connected to the collector of the transistor. We connect the transformer windings according to the phasing and connect them to the power supply. In most cases, the winding phasing can be determined by looking at the transformer connection contacts, looking at which side the winding wire comes to the contact, from the left or right side. For example, the left is the beginning of the winding. If it does not work, change the connection of any one winding of the transformer to the opposite connection. We connect the negative power supply to the emitter of the transistor. We add a diode, preferably Schottky, and a resistor to limit the output current. That's it, we got a simple LED tester. To achieve the best parameters, we put a variable resistor in the base circuit of the transistor, connect a voltmeter to the output. By changing the resistance of the resistor, we achieve the highest voltage at the output of the LED tester. We measure the resistance of an alternating resistor, solder a permanent resistor with the same resistance. With a power supply voltage from a finger battery, the output voltage is fifty volts, from a lithium battery about one hundred and fifty volts. The output voltage depends on the transistor used. When using a transistor "CT 3102" and a voltage above two volts, generation is disrupted. Changing the resistance of the resistor in the base of the transistor did not solve the problem. At low voltages, this transistor showed the best result. A good result was obtained with the transistor "C 9014", there is no problem of generation failure when the supply voltage is increased. Almost any N-P-N transistor or P-N-P transistor can be used in the tester by reversing the polarity of the power supply and diode connection. The tester turned out to be small, one and a half centimeters long, one centimeter high and one centimeter wide, not taking into account the battery. When using the tester, we connect it in parallel to the probes of a multimeter switched on in voltmeter mode, or to any voltmeter. An assistant for checking the operability of LEDs and other elements is ready. You can also check the performance of zener diodes, diodes, dinistors and other elements with a tester of LEDs.