If you have the skills and can get your hands on SMD components, you can assemble this small amplifier. We found it in the Radio Electronics Experimenter special edition from 1990.
This 9-bit DAC circuit was found in the RCA CMOS integrated circuits manual of the 1970s. The...
A NOR gate can be improvised using one NAND gate of a 4011 as shown here. The diodes are...
Found in na 1980’s English magazine, this circuit produces a strong modulated tone reproduced on a...