Before revision: Somewhat later, farm radios were made to be run on 6 volts from a car or tractor battery, using an electromechanical vibrator to create a pulsating DC current that could be stepped up though a transformer to create the high voltage needed for the plates of the tubes- exactly as contemporary car radios did.
After revision: Somewhat later, farm radios were made to be run on 6 volts from a car or tractor battery, using an electromechanical vibrator to create a pulsating DC current that could be stepped up through a transformer to create the high voltage needed for the plates of the tubes- exactly as contemporary car radios did.