I will show you a way to make the LED glow without connecting wires to it. For this you will need to assemble a simple device on a single transistor. And you can play your friends by showing them your magical abilities.
A schematic diagram of a single transistor. It is almost a classic high-frequency oscillator with inductor and feedback. Inductor is a wire made in the form of a round loop. The LED also has a receiving loop. When these loops are combined together at a certain distance, the energy is transmitted to the LED and it starts to glow. The whole circuit is powered by finger batteries. Perhaps you will have a question - where is the feedback connection in this generator? The generator operates at a very high radio frequency. And a capacitor for feedback is not required, so the transistor case itself has a small capacity.Plus, the inductances are very close to each other.
Details for the circuit
1. Batteries - 6 pcs. 2. One red LED. 3. Transistor, type BF494 or similar. 4. The capacitor is 0.1 µF. 5. Resistor 33 kΩ. 6. 330 μg inductance. Wires, solder, etc., as needed. For an inductor loop, any piece of solid wire that is not very thin.
The LED itself
The LED will require some work. Its output must be bent into a ring and soldered. All. Receiving high-frequency radiation indicator is ready.
Making a generator
It is very desirable to solder everything as I have in the picture. I also assembled two rings with an LED. One is red, the other is blue. So, just in case.
Connect the generator to a power source. And bring the LED, if it is lit - everything works.
Next, we check the distance, but which the LED is working on.It will be on the order of a few centimeters. Now it remains to fix the circuit and the batteries under the table and surprise your friends with a cheerful and unusual gift.
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