Setting the brightness of the LED switch

MiroRi — Mon, 22 Apr 2024 13:33:28 +0000

I discovered an interesting switch on the market with an LED light in the lever. I have four LED colors, red, green, blue and white. According to the manufacturer, it is designed for 12V DC, i.e. direct current. However, the indicator light shines with a very strong brightness, it is unpleasantly dazzling when working indoors.

Wiring:

What about that? Simply put a resistor in the path before the GND terminal, e.g. 1k2 and it's done. WARNING! This point will no longer be ground (GND) for the device but only for the LED switch. We calculate
the resistance R according to the formula R=U/I.

For more info, see hobbyport.electronics...
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Simple current load

MiroRi — Tue, 02 Apr 2024 11:32:29 +0000

Very simple current load in retro style. Semiconductors, resistors and the meter are from the no longer existing state of Czechoslovakia (Czech Republic - Slovakia). It was manufactured by Tesla np (national enterprise).

The voltage BE is obtained from the slider of the potentiometer through the resistor R1, which partially protects the transistor from current overload. The voltage that is divided on the potentiometer is obtained from the voltage drop on CE. This voltage is limited by the zener diode ZD (in this case 5.9V / I didn't have a smaller one /) and resistor R2. Why ZD? It protects the transistor from overvoltage at BE and partially stabilizes the CE current. This means that a change in the voltage of the tested source will more or less (it has certain reserves) not affect the change in the current flowing through the.

I also included a needle measuring device in the circuit, which was originally a 250V DC voltmeter. After removing the primary resistor , I found that it needs 350 µA for full deflection . That's why I connected it with a 0.1 Ω shunt . Now it shows a current of 2500mA at full deflection. Material: KD502 NPN transistor (max. parameters: BE 5V, CE 70V, IC 20A, 150W) ZD 1NZ70 zener diode (Uz 5-6V, Iz 100mA) R1 100Ω / 5W R2 220Ω / 5W Rb 0.1Ω / 5W P1 WXD3590 10 - rotary wire potentiometer 10kΩ.

I'm sorry for my english.
For more information see here: hobbzport electronics

DEV Community: MiroRi

Setting the brightness of the LED switch

Simple current load