This interesting circuit with a neon lamp and a transistor was found in Radio Electronics magazine from February 1968. The transistor is a special type of high voltage at the time.
Many designs that use transistors and integrated circuits are powered by a 6V voltage, normally...
This preamplifier with RIAA equalization was obtained in a documentation from the 1980s. The...
This circuit is from an old documentation from 1995, but it can be easily assembled today by the...