Mini Metronome by 555 Timer/Oscillator IC

This mini metronome gives a linear scaled output and 40 to 208 beats per minute.

3 Watt HI-FI Stereo Amplifier

Tr1 and Tr2 transistors functions as direct coupled voltage amplifiers. R6 resistor, D1 and D2 diodes determine the standby current of complement driver stage (Tr3/Tr4) and output stage (Tr5/Tr6).

TDA2052 60 Watt Amplifier with Mute and St-By Functions

TDA2052 is a AB class amplifier which operates with (+,-25V) supply and generates 60 Watt power (sound) output.