Accumulator / battery operation
In the early days of wirfeless communication, accumulators and batteries were almost the only usable power source, especially when a set was to be used outside a house.
Older tube equipped receivers are powered by heater accumulators for the tube heaters, accumulators or batteries with high currents and voltages from 2 to 6.3 volts are needed. Furthermore, the tubes require different anode or plate voltages, which could be obtained from plate batteries or mains-powered power supplies.
In the classic mains-powered tube sets of the forties to sixties, mains transformers with a heater and a plate voltage winding with corresponding rectifiers were in use. For the portable sets of the mentioned time period, mostly heater batteries (often 1.5 volts) and plate batteries (special formats, often 51 and 103 volts) were used.
Transistor sets which appeared after the 1970s are battery operated and usually require standard batteries. The rechargeable NiCd accumulators, which are also popular, provide a lower voltage of 1.2 V per cell, so that in individual cases it must be tried out whether a set can be operated from 1.2 V NiCd accumulators instead of batteries in the battery compartment works.