This debouncer circuit uses a transistor to produce a single pulse when the switch is triggered. The transistor conducts when the switch is opened. We found this configuration in an 80's publication.
This different audio amplifier was found in a 90's Electronic Design. The circuit uses components...
We found this circuit in an 80's Radio Electronics. The circuit uses a PTC sensor and an LED...
The receiver circuit LM567 recognizes the tone set on 555. The connection between the circuits can be made...