Using the 555 and 4020, this timer was found in the July 1994 Radio Electronics magazine. The relay is voltage-dependent, and the transistor is general purpose.
This circuit was found in National Semiconductor documentation from the 90s. The circuit uses two...
This type of sensor was used in sensitive infrared systems from the 1960s. This circuit was found...
This 4.5 MHz amplifier is suitable for analog TV applications. We found it in a 1967 Philips...