Free Circuit Diagram

This wireless microphone circuit uses only a single transistor, with few additional passive components. This FM transmitter is very compact and need only a single cell 1.5Volt battery, even works on 1.2V rechargeable battery. Here is the schematic diagram of the circuit:

The transmission range could be between 30-50m radius in open air, and practically depends [...]

Please be warned if operating this circuit might violate the regulation of your country, because this FM transmitter circuit radiate strong radio frequency to the environment. This wireless microphone is very sensitive, pick up every sound in the 20m radius, and transmit the radio signal up to 2 kilometers in open air. Here is the [...]

ROHM (www.rohm.com) is originally a resistor producer company, but finally expand their business and produce monolithic IC, and this one used in our circuit is the example. The internal structure of this FM transmitter integrated circuit consist of stereo modulator that creates a stereo composite signal, an FM modulator that modulate a carrier frequency with [...]

Using this switch mode regulator circuit, you can get a stable 12 volt output (500mA) although you just have 4,3 – 10V power supply. You can even boost a 3.5V input to 12V if the load draws only 100 mA or less. This switch mode voltage regulator use LTC1266 IC chip from Linear Technology. Here [...]

This switch mode regulator circuit has higher current output than  our previous switch mode regulator, but it uses same controller IC. Up to 10A can be served by this switch mode regulator. The output of this regulator circuit is regulated at 3.3 volt, and the input range is 4-9Volt.

The SHDN pin can be pulled high [...]

This switch mode step-down converter has very good efficiency, up to 94% can be obtained. This switch mode regulator uses LTC1266-3.3 controller with external N-Channel power mosfet, and need only a 5uH inductor because it uses high frequency switching. Here is the schematic diagram of this switch mode step down converter circuit:

To optimize efficiency, the [...]