Found in a 90s 303 Circuits, this circuit triggers a load from a 50 mV audio signal. When the signal ceases, the charge remains active for 2 seconds.
This circuit converts square (rectangular) signals into triangular signals with typical 16 V...
The transistors of this circuit found in an English 1980s documentation may be the modern BC548...
In the figure we have an AND gate with the LM3900 operational transconductance amplifier. The...