This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
In this circuit of 1987 the player has to briefly press one of the keys trying to hit which LED...
This circuit consists of a controlled charge to discharge batteries under test. The circuit is...
In this alarm R1 and R2 can be 10k. The SCR is any 106 Series SCR and V1 is an oscillator buzzer....