The signal from this transmitter is injected into a cable that you want to follow along a pipeline. Monitoring is done using an ordinary AM receiver out of season.
This simple photometer uses a 1 mA milliammeter and a common phototransistor. The circuit has its...
The component values depend on the current, which in this case has a maximum value of 5 A. The...
I found this circuit in an article in a 2003 publication. The circuit is an example of how to...