We found this good amplifier in a Japanese publication of 1966. Transformers are uncommon nowadays and the power supply is included. Power is a few watts.
March 2017 - The new Texas Instruments TPA3244 class D amplifiers with power ratings from 60 to...
The coil is formed by 70 + 5 turns of 6 to 30 AWG wire on a 1 cm to 10 cm ferrite core. The...
Thes astable was found in old publication of 1968. The circuit uses general purpose germanium...