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The circuitry shown in FIG. 2 as shown therein includes three iron core transformers identified as T1, T2 and T3. The transformer T1 can be characterized as being a power transformer which has its primary winding 31 connected to a suitable source of voltage such as 115 volts AC, 2000 Hertz. The transformer T1 reduces the voltage on its secondary winding 32 to a suitable voltage such as approximately 20 volts AC. Typically this voltage should be a voltage which can be utilized with standard transistor amplifiers and logic circuits. The secondary 32 of the transformer T1 is connected to lines 33 and 34 at its outer extremities and has a center tap connected to a line 36. The center tap line 36 is connected to a ground G2. The lines 33 and 34 are connected through high impedance resistors R1 and R2 to the primary 37 of the transformer T2 which can be characterized as a "
piggyback" transformer. Transformer T2 provides unity transformation and thus supplies the same voltage which is supplied from the secondary of the transformer T1 to the secondary 38 of the transformer T2 as, for example, 20 volts. By the use of this second transformer T2, the secondary 38 is floating with respect to the primary 37 and makes it possible for the secondary to be utilized to control electronic devices as hereinafter described isolated from the ground G2.
