Two-tone solar buzzer (CB20493E)

This circuit was found in a 1991 publication. The transistor can be a general-purpose type.

Buffer for the ICL8038 (CB4990E)
The ICL8038 is a function generator that appears elsewhere on this site in various applications. The...
Economic inverter (CB7178E)
This circuit with 117 V output was found in a 1969 Electronic Design. Drive transistors admit...
Diac Voltage Sensor (CB12992E)
The circuit shown in the figure is triggered by an input voltage determined by the setting of P1....