Datasheet of This amplifier uses a pair of complementary transistors at the output and can provide 1 W of audio at a load of 3-ohm. Higher impedance speakers can be used. The circuit is from an English publication from 1986 and TR1 can be a | BC548. The supply can be done with voltages from 9 to 18 V. The trimpot adjusts the resting current, which must be in the order of 20 mA.
This circuit can be used in alarms by activating a relay or a current load that depends on the...
This circuit is from the 1968 ARLL documentation. The MOSFET admits equivalent and the coil...
Figure bellow shows how one of the two separated counters found inside the 4518 is used as a...
