project key


Posted on Feb 4, 2014

This battery-powered monitor has been designed to provide an audible indication of keying for those whose rigs lack a CW sidetone. Its sensor wire is wrapped around the transceiver`s coax no direct connection is required. Of course Morse isn`t the only use for this nifty circuit it should also be useful any time you need a simple alarm tha


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

t detects the presence of RF. RF collected at the sensor wire is rectified by a germanium diode. This produces a DC voltage that triggers a transistor switch. This then turns on a 555 audio oscillator that drives a speaker.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

3.5 To 10Mhz Simple Superheterodyne Receiver
Dc to Dc converter using 555 Timer IC
am/fm radio & Pilot 100 stereo demodulator
Touch Sensitive Musical Bell With Timer PCB
FET biasing
TDA Amplifier Circuits
Arduino UNO Tutorial NightLight
Phono Preamplifier
Dummy Transmission Circuits for Subcutaneous Transmitter
Reverse Engineering a 1.5 inch Photoframe



Top