This low cost hearing aid circuit offers the advantages of high sensitivity, low current consumption and light weight.
Audio signals are sensed by the condenser...
This solidstate signal lamp is a good alternative to revolving mechanical signaling lamps used in ambulances. It uses ultra-bright blue LEDs for signaling. However,...
This parallel telephone circuit provides secrecy when two or more telephones are connected in parallel to a telephone line. The circuit also prevents incoming...
The circuit automatically disconnects power supply to the audio/video system whenever the mobile handset is lifted off the holder for making or receiving a call.
Burglar alarms have become standard equipment in stores and other businesses, and they're becoming increasingly common in private homes as well. If you've ever...