This is the circuit of the commercial Japanese megaphone of the 60s model DM-218. The circuit uses a compression speaker (horn) and is powered by 4 large batteries. The output power is 2 W.
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...