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 polarity test or indicator indicates the polarity of a power line by LEDs. The circuit is...
This is the circuit of a digital clock published in the January 1975 issue of Radio Electronics magazine....
Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The...