Type 1			Battery operated
			Battery operated devices for producing mild electric shocks for stimulation of the nerves and muscles for alleged medical benefit

All these battery operated devices work on the same basic principle. A basic circuit of the type we used to make for amusement is shown below -

For comparison the circuit can be compared with the conventional ignition system on a car, where the 12 volt battery voltage is transformed up to 25,000 volts or more at definite intervals to fire the plugs.

In the circuit shown above the trembler unit is adjusted to vibrate continuously to produce a continuous A.C. voltage on the high voltage winding.

It really isn’t practical to have maximum output all the time as the 'patients’ could be in agony. Our homemade devices often had a variable resistor in the battery supply to lower the voltage available to control the output, this was wasteful in power terms and often entailed readjusting the trembler unit.

The medical units I describe have a variety of methods of controlling the output, some of them very ingenious .

Note :-  All of these units except Box No. 5 & 9  have output selection terminals or switch with two positions marked  P  and  S.
Position P connects the output across the low voltage ‘primary’ winding and would be used if very sensitive areas were being treated.
Position  S  connects the output across the high voltage ‘secondary’ winding for more general use.

Box No. 5 and No 9 have a selector switch on the output winding  to choose a suitable level of power output.
All these boxes  have a variable control  to vary whatever power level available from almost zero up to the maximum.