This circuit for automotive use was found in American documentation from the 90s. The circuit uses common components today. The relay is 12 V.
This 1-transistor reflex receiver was found in a 1963 publication. The coil is for the mid wave...
Found in a European magazine from the 90s, this circuit emits beeps that are several seconds apart to...
This interface or shield circuit for instrumentation was obtained in a publication from the 90's....