Suggested by Mullard in a1969 documentation, this circuit generates the erasure signal for tape recorders of the time. Transistors can be modern equivalents like BD136 and BD136.
This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM...
In the figure we have the way to obtain an adjustable constant current source of 2 mA. The...
Found in a Maxim publication from the 90s, this circuit generates signals from 10 to 25 kHz with a...