REGULATOR No. 1 and 1A

Regulator No. 1
The regulator consists of a small printed wiring board on which are mounted a Resistor, Bulb No. 15, a Rectifier-Element No. 209 and two carbon resistors of 15 and 47 ohms connected as shown on Diagram N801.  These components are soldered directly into the printed wiring pattern which is connected to the telephone circuit by five plug points formed on one end of the board.

Three more plug points, which are strapped together, are provided at the other end of the long side of the board so that reversal of the regulator board in its jack will remove it electrically from the telephone circuit.  All the printed wiring plug terminations are coated with a thin layer of solder to provide good contact with the jack springs when the regulator is plugged in.

In the original regulators the Resistor, Bulb was clear and when it illuminated there were complaints from users of red coloured telephones that the insides looked on fire.  Because of this, the Resistor Bulb was coated in a black paint.

Used in the Telephone No. 706.

Regulator No. 1 front and rear views

Regulator No. 1A
This regulator is electrically identical to the Regulator No. 1 except that the plug points are now located on the long sides of the circuit board instead of the short sides.  These were used in the Telephone No. 711, wall telephone, where a reduced height circuit board was required.

Used in Telephone No. 711 and Bellset No. 48.

Regulator No. 1A front and rear views



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Last revised: December 06, 2023