Found in a 1965 General Electric Hobby Manual, this timer was originally created to operate with photo magnifiers of the time. The circuit can be adapted for other purposes.
This circuit reinforces signals in a frequency range between 1500 and 2000 Hz for use in...
When a small air current reaches the piezoelectric sensor, a small audio signal is generated and...
This circuit is from a Poptronics, American magazine from August 2000. The circuit can be...