Single Transistor Wireless Microphone (FM Transmitter)

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 on the surrounding transmission […]

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Two Transistors Wireless Microphone (FM Transmitter)

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 schematic diagram of the circuit: […]

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Single Chip Stereo FM Transmitter Circuit: A Very Compact Design

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 the composite signal, and an […]

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High Efficiency Switch Mode 3.3V 5A Step-Down Converter

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 LTC1266  automatically switches between […]

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Pt100 RTD Current Loop Transmitter Using XTR105

XTR105 is a 4-20mA current loop transmitter integrated circuit, with two precision current sources. The Instrumentation amplifier gain inside this chip can be configured for a wide range of temperature or pressure measurements. This integrated circuit chip provides current excitation for platinum RTD temperature sensors and bridges, instrumentation amplifiers, and current output circuitry on a single integrated circuit. Two matched […]

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