We found this circuit in a 1976 documentation. The FET can be BF245 or MPF102 and the power supply need not be symmetrical. The FET in the feedback acts as an automatic gain control.
This analog volt-ammeter was found in an Electronics World of 1968. It makes use of a 0-1 mA...
This is one of the many possible siren configurations for the 555 integrated circuit. We found it in...
This circuit was found in an Electronics World magazine from 1990. The circuit can be mounted...