Found in a Hands-On Electronics from the 90s, this circuit produces the dial tones of an old telephone. The integrated circuit used is uncommon today.
This circuit is from Signetics' 80s documentation. The circuit generates 100 kHz signals according...
This circuit was found in a Motorola documentation from the 90s. The transistor used is uncommon...
This two-tone buzzer can be powered by a solar panel. The circuit is from a 1991 documentation. The...