This circuit was found in a 73 amateur radio magazine from the 90s. An LED extends the scale from 0 to 5 V to 10 to 15 V in this bargraph circuit. Other zener values can be used.
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
We found this circuit in Ferranti's 1974 transistor manual. The components are from the period. Note...
This instrumentation amplifier was obtained from Popular Electronics in 1993. The operational...