Two-tone solar buzzer (CB20493E)

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

Power booster (CB8775E)
This circuit was found in a 90s EDN. Its purpose is to increase the efficiency of operational...
Peak Signal Indicator (CB25966E)
This LED indicator circuit uses an LM339 comparator. The circuit was found in the January 1995...
Signal Drop Detector (CB6117E)
This circuit was found in an 80's General Electric documentation. The circuit uses uncommon...