Free Circuit Diagram

This is a protocol translator circuit. This circuit uses the MAX3162, it contains both  RS-485 and RS-232 transmitters  and receivers. This IC contains wide range of communication devices, that can convert bidirectionally between RS-485 and RS-232 signals. Here is the circuit : The upper circuit is the translator for point to point [...]

This is a circuit that transmits temperature data over an IR link and it allows the isolation of temperature sensor. It is a good solution of obtaining temperature readings from points at potentials a few tens of volts from ground by linking a temperature probe  only by an IR connection to the readout point. This [...]

This FM transmitter circuit is small, similar to our previous single chip FM  transmitter, but this FM transmitter is monophonic. You can see in the circuit’s schematic, the left and right signals is mixed before modulate the radio frequency. Here is the schematic diagram of the circuit:   The core of this [...]

This instrument is very useful for radio frequency (rf) engineer and hobbyist, especially when he/she has to adjust the final rf transmission. Setting up an antenna impedance matcher is one of the example. Here is the schematic diagram of this rf meter circuit: The circuit use only one transistor (MPSA18) as the [...]

RCV420 is a special function integrated circuit chip for 4-20mA current loop receiver. RCV420 provide complete 4-20mA to 0-5V conversion, with 0.1% overall accuracy, 86dB CMR, and ±40V common-mode input range. This IC chip is suitable for many applications: PROCESS CONTROL INDUSTRIAL CONTROL FACTORY AUTOMATION DATA ACQUISITION SCADA [...]

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, [...]