FM Transmitter

This project provides the schematic and the parts list needed to construct a 3V FM Transmitter. This FM transmitter is about the simplest and most basic transmitter to build and have a useful transmitting range. It is surprisingly powerful despite its small component count and 3V operating voltage. It will easily penetrate over three floors of an apartment building and go over 300 meters in the open air.It may be tuned anywhere in the FM band. Or...

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Remote Control IR Transmitter

Program IR TransmitterThis project is based on integrated circuit from Holtek HT6221/HT6222. Similar parts used to be produced by NEC Semiconductor uPD6121/uPD6122. These ICs are commonly used in VCR infra red remote controls, garage door controllers, car door controllers, security systems and other remote control .They are capable of encoding 16-bit address codes and 8-bit data codes. Each address/data input can be set to one of the two logic states,...

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Automatic Headlight Brightness Switch

Automatic Headlight Brightness SwitchDriving the highway with your high-beam headlights can really increase your visibility, but can he a blinding hazard for other drivers. This simple circuit can be wired into your headlight switch to provide automatic switching between high and low beam headlights when there is oncoming traffic. It does this by sensing the lights of that traffic. In this way, you can drive safely with your high-beams on without...

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Small FM Transmitter

Small FM TransmitterNothing critical here. To get a bit of tuning out of the coil you could put a 4-40pF trimmer capacitor (optional) parallel over the 1 µH coil, L1.C1/C4 and C5/C6 are ceramic capacitors, preferably NPO (low noise) types. C2/C3 are electrolytic or can be tantalum types.The antenna is nothing more than a piece of 12" wire or a piece of piano wire from 6" to 12".To find the signal on your receiver, make sure there is a signal...

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Transformer

In real this is how an TRANSFORMER looks like..the transformer is a device that transfers electrical energy from one end of the coil to the another coil by mutual induction method......Introduction of transformer..A transformer makes use of Faraday's law and the Ferromagnetic properties of an iron core to efficiently raise or lower AC voltages. It of course cannot increase power so that if the voltage is raised, the current is proportionally lowered...

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Doorbell for the Deaf

Doorbell for the DeafThis circuit provides a delayed visual indication when a door bell switch is pressed. In addition, a DPDT switch can be moved from within the house which will light a lamp in the door bell switch. The lamp can illuminate the words "Please Wait" for anyone with walking difficulties. The circuit uses standard 2 wire doorbell cable or loudspeaker wire. In parallel with the doorbell switch, S1, is a 1N4001 diode and a 12 volt 60mA...

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Touch Switch

Touch SwitchThis circuit uses a 555 timer as the bases of the touch switch. When the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10M resistor on pin 2 causes the the circuit to be very sensitive to the touch.Circuit Diag...

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