This circuit was found in an article in Radio Electronics magazine. The issue is from July 1992 and the circuit uses components that are common today.
This 1 kHz circuit was found in American documentation from the 90s. The original operational...
This solar cell powered circuit generates a standard 100 kHz signal. The circuit is from a 1960...
This experimental touch switch uses two general-purpose NPN transistor. The lamp can be replaced...