This circuit with 1% regulation aims at replacing mercury cells. We found it in a 1967 documentation. Transistors can be replaced with modern equivalents.
In the figure we have a second order filter with very high input impedance, using an operational...
This circuit that can be activated by light or heat was found in an old American documentation, but the...
This interesting circuit, found in a 1986 publication, includes a powerful audio amplifier. Being...