Electronic Circuits and Tutorials
Electronics Schematics - S

RF (Radio Frequency)
Detectors & Sensors Circuits

10.7MHz FM Detector:

Cellular Phone Helper #1: activates a variety of devices when your cellular ph1-is in use, PDF file

Cellular Phone Helper #2:

Linearized RF Detector:

Make a truly linear RF power detector: 09/19/2002  EDN - Design Ideas / Modern high-performance transmitters require accurate monitoring of RF power, because most cellular standards depend on strict power- transmission levels to maintain an effective network. Regulation of transmitted-signal strength also lets you build lower cost systems. Figure 1 shows a waveform-independent circuit that provides a linear measurement of RF power.

R / C Switch: This circuit is a so-called "Radio Controlled Electronic Switch". It can be used to switch on/off anything electrical, whatever it is. Here are a couple of examples: navigation lights, landing gear, sound systems, Glowplug driver, bomb release, parachute, search lights, gyros, and so on. This circuits connects to a RC car controller servo output.

RF Actuated CW Monitor:

RF Design Hint Increases Transmit Signal Rejection In Telephone Hybrids: 11/20/00 Electronic Design - Ideas for Design / Every telephone signal port used to transmit and receive voice or modulated data from a modem employs a hybrid (duplexer) circuit. Such circuits are used to separate the transmit and receive signals.

RF Detector:

RF Dummy Load: make this simple RF Dummy Load for off-air testing of your radio transmitter.

RF Power Meter for the QRPer:

RF Sniffer:

RF Sniffer <.5 to >500 MHz:

RF Spectrum Analyzer:

Surveillance Transmitter Detector: This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative. The problem in making a suitable a detector is to get its sensitivity just right, Too much sensitivity and it will respond to radio broadcasts, too little, and nothing will be heard.

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