Measurement and indication of operating voltages - for individual assemblies in radio and TV receivers using LEDs with ring counter and three differential amplifiers

摘要

Measurement and indication of operating voltages of individual assemblies in radio and t.v. receivers uses light emitting diodes as indicating elements. The l.e.d.'s are accommodated in a housing and are connected to the receiver to be tested. The operating voltages are switched to the inverting or non-inverting input of an operation amplifier via a ring counter. A fixed reference voltage is switched to the inverting input of a first operational amplifier. A second reference voltage is switched as output voltage of a third operational amplifier to the non-inverting input of a second operational amplifier.