Found in 1980s Electronics Design, this circuit covers 4 decades of frequencies with a unique control. A multi-turn trimpot is used for fine adjustment. The frequency range depends on C1.
This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The...
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...
This control for a small servomotor with a current of a few hundred milliamps was found in an...