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- เผยแพร่เมื่อ 13 ก.ย. 2024
- LED tester, from improvised means. We check LEDs and other elements.
We need a transformer, a transistor, a diode and two resistors. All parts can be taken from non-working devices, or bought. Just wind the transformer yourself.
I used a transformer from a non-working LED driver, you can take a transformer from charging the phone.
transformer winding with lower resistance is connected to transistor base through 20 kOhm resistor.
We connect the winding with high resistance to the transistor collector. The transformer windings are connected according to the phasing and connected to the plus 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, on the left or right side. For example, left is the beginning of the winding. If it does not work, change the connection of any transformer winding to the opposite connection.
We connect the minus of the power supply to the emitter of the transistor.
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, put an alternating resistor in the transistor base circuit, and 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 a variable resistor, solder a constant resistor with the same resistance.
When powered by 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 the transistor "KT 3102" and a voltage above two volts, the generation is interrupted.
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 "C 9014" transistor, there is no problem of generation failure when the supply voltage rises.
In the tester, almost any N-P-N transistor and P-N-P transistor can be used, changing the polarity of the power supply and diode connection to the opposite.
The tester turned out to be small, one and a half centimeters long, one centimeter high and wide, not taking into account the battery.
The tester, when used, is connected in parallel to the probes of the multimeter turned on in the voltmeter mode, or to any voltmeter.
The assistant for checking the health of LEDs and other elements is ready.
You can also check the performance of zener diodes, diodes, dinistors and other elements with a LED tester.
Этому "ноу-хау", как минимум, 10 лет!
Доброго дня, Все новое это хорошо забытое старое. Разве плохо за пару часов сделать из готовых деталей полезный прибор. Да схема не нова.
Вроде все просто)
@@ИннаНавойчик Доброго дня, да схема простая, не капризная, показала не плохой результат. Друг попросил сделать что то для проверки светодиодов.
Показал бы схему и рассказал о нюансах и все. Так нет, стал показывать как может паять паяльником….
Доброго дня , схема в самом начале нарисована, про нюансы в описании и голосом рассказал и показал на каком транзисторе получился лучший результат из тех которые нашел . Ваши пожелания возьму на заметку. Хорошего дня.