Mains Transformer P2B

• Brand: Birmingham Sound Reproducers

Mains transformer, type P2B.

A very neatly made mains transformer is the Birmingham Sound Reproducers model P2B. This transformer is provided with a tapped input winding making it suitable for use on 50-cycle supplies with voltages varying from 200 to 240 volts.

On the secondary side, two windings are provided, one centre-tapped to supply a maximum of 4 amperes at 4 volts to the heaters of A.C. type valves, and a high-tension winding suitable for use in a normal single-wave rectifying circuit or with a voltage-doubler metal rectifier circuit.

This winding gives 200 volts, with a tap at 170 volts if required. All connections are brought out to a small terminal board mounted on the top of the transformer. Fair size terminals are employed, each being clearly marked.

Output Voltage

The transformer was tested on its 200-volt secondary winding with a Westinghouse HT8 metal rectifier and connected up with two 4-microfarad condensers. With a load of 60 milliamperes D.C., the unsmoothed output voltage obtained was 288 volts. The actual variation of voltage with load can be seen from the curve accompanying this report. With regard to the 4-volt winding, the voltages obtained were very slightly low, the actual value on the full load being 3.7 volts at 4 amperes. This is probably deliberate to avoid excess voltage if only two or three valves are used.

Price £1/7/6

Here you find 105 models, 97 with images and 21 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from BSR (Brand), Birmingham Sound Reproducers Ltd.; Staffordshire