We found this circuit in an article that describes several alarms that are in the sequence in our section. The article is from the Radio Electronics magazine of May 1971.
This stable 20 MHz oscillator was suggested by the National Semiconductor's Linear Applications Handbook...
This buffer and driver is from the integrated circuit manual itself, the Linear Technology LT1206. The...
The transistors in this 1978 circuit can be BC548 and 1N4148 diodes. The electrolytic capacitors can be...