We found this circuit in an Australian publication from 1991. It is a kit of the time with input for a guitar pickup. The range is a few tens of meters.
This circuit was found in a 1968 General Electric manual. The circuit is for 3 A motors but can be...
With this circuit it is possible to monitor a signal that is being recorded on an old tape...
We found this circuit in the September 1995 issue of Electronics Now magazine. The circuit has 6...