Found in a 1980s documentation, this circuit uses transistors from that time. Modern equivalents can be used. The alarm is a piezoelectric buzzer with na included oscillator.
Found in old documentation, this circuit is the receiver for the previous circuit. Components are...
We found this circuit in the 1994 Linear Applications Handbook by National Semiconductor. The...
This circuit switches the capacitors of a digital filter with the 4046 IC (PLL). The circuit was...