This circuit reproduces the dial noise in a small speaker. The transistor can be a general-purpose type. We found it in an 80's Electronic Design.
We found this circuit in an Analog Devices documentation from the 90s. The circuit is based on a...
This circuit turns off a load after an interval of 8 to 80 seconds adjusted on the potentiometer. The...
Found elsewhere in this section, this circuit is from the April 1971 Radio Electronics magazine. Note...