Posted on Feb 4, 2014

This rf detector can locate low-power transmitters (bugs) that are hidden from sight. It can sense the presence of a 1-mW transmitter at 20 feet, which is sensitive enough to detect the tiniest bug. As you bring the rf detector closer to the bug, more and more segments of its LED bar-graph display light, which aids in direction finding. The front

Click here to download the full size of the above Circuit.

end has a two-stage wideband rf amplifier, and a forward-biased hot-carrier diode for a detector. After detection, the signal is filtered and fed to IC1, an LM3915N bar-graph driver having a logarithmic output. Each successive LED segment represents a 3-dB step.

Leave Comment

characters left:

New Circuits



Popular Circuits

Soft Start for PSU
Telephone-Operated Ac Power Switch
0 To 12V, 1A Variable Power Supply Circuit
Solid State Tesla Coil/High Voltage Generator Circuit
A Simple Metal Detector Circuit Using Beat Frequency Oscillator (BFO)
Restoration of the DuMont Industrial Color Monitor
square wave oscillator circuit
Solar charging a Nokia N95
Flow DC solenoid circuit operation