The circuit is from Ferranti's 1974 transistor manual. Transistors are general purpose types, and the output waveform is rectangular. Components can be changed to other frequencies.
Written in an article in Radio Electronics magazine in April 1987, this circuit triggers an alarm...
This is the receiver circuit for the previous transmitter. The circuit has a programming key to...
This is an example of a temperature sensor shield using the Texas Instruments TMP390 obtained from...