Tag Archives: LED

Fuse Monitor

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The idea for this project may have come to me in a flash of inspiration, and its a very simple way to check if a fuse has blown without removing it from its holder. The simplicity of this circuit uses just two components, but with just one resistor and an… Read more »

Flashing Eyes

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This circuit was purposely designed as a funny Halloween gadget. It should be placed to the rear of a badge or pin bearing a typical Halloween character image, e.g. a pumpkin, skull, black cat, witch, ghost etc. Two LEDs are fixed in place of the eyes of the character and… Read more »

Mini Lithium Torch

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This mini pocket torch combines the advantages of Lithium button cells with a super-bright white LED. The lithium cells are small, have a long shelf life and have very little self-discharge. The LED has very high efficiency, an extremely long life expectancy and a modest current consumption (20mA). In combination… Read more »

Wide Voltage Range LED

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LEDs are well-known for their current consumption, and sometimes a resistor is necessary to limit the current at a moderate value, between 10 to 30 mA. This solution has a drawback, because the value of the resistor must be calculated for each value of voltage. Replacing the resistor with a… Read more »

LED Constant Current Circuit

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This is a very simple led constant current design using only 2 transistors, 2 resistors and an LED. This circuit allows you to use any voltage between 2V and 24V to drive almost any type of LED with power consumption up to 5W. The T2 transistor can be BC547 if… Read more »

LED 220V Volt

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LED has become more and more popular for use as light indicator because of its low cost and long life. Unfortunately the LED works only at low voltages and even then you need to use a resistor in series. It is not a good idea to limit the current at… Read more »