This crystal or galena radio was found in documentation from the 1990s. The earpiece must be a high impedance crystal or magnetic earpiece and D1 can be any germanium diode.
This sophisticated inverter circuit of excellent performance was found in a French publication in 1995. The...
The integrated circuit used in this application is the Texas Instruments LMV358A, a low voltage...
This circuit is from 80s documentation, using still common CMOS components. The display is 7...