This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The original circuit is from a 1979 publication and is powered with only two AA or AAA batteries.
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
Using a 100 uH inductor for L1, this circuit will oscillate around 1 MHz. The frequency will be...
This low current solenoid driver was found in an ancient American documentation. The solenoid must be...