This transistor class B 5 W amplifier was found in a 1969 Mullard documentation. The transistors are from that time, and modern equivalents may eventually be used.
We found this circuit in the National Semiconductor Linear Applications Handbook of 1994. The...
This is 4-input audio mixer using an integrated circuit 741 and two more operational amplifiers....
This shield circuit for controlling the direction of rotation of DC motors with current up to 500...