This transmitter emits a modulated signal at a frequency given by the first transistor in the phase shift oscillator. The circuit is from an Australian publication from 1991.
This circuit was found in a Mullard transistor manual from 1960. Note the symmetrical power...
This amplifier step with a transistor has an input impedance of 100k to 10 M. The transistor can be any...
I found this little signaling transmitter in old American documentation. The circuit has a good...