This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
This circuit was found in an English documentation from the 90's. The circuit has the frequencies...
This simple preamplifier with two transistors may be used in a wide range of applications. The...
This circuit generates approximately 30 Hz signals from a 3.3 kHz clock. The circuit was found at...