In the later twenties, the radio receiver
power supply comprises a set of batteries. Thus, while the A battery
supplies the voltage for the valve filament, the B batttery supplies
the high voltage and low current for the screen and plate, as known
as B (+).
Also a C battery could be used when the power supply used separated
bias for the screen.
Such a kind of power supply had several disadvantages: the size
as well as the voltage and current required for the B (+). Thus,
during the early thirties, a demand ocurred in the radio industry
for a substitute of the “B” battteries. Firstly, engineers
investigated the possibilities of the motor generator as known as
dynamotor. Therefore, due to its size and high manufacturing cost
it was unsuitable for such application.
|Fig. 317 - The vibrator a kind of component
developed to converter the 6 V CC into high voltage CC.
In this way, after many researches, finally it was developed a kind
of half-wave buzzer connected to a transformer and a rectifier valve
as known as a power supply using a vibrator.
In the following years various types of vibrators were developed
such as: the full-wave non-synchronous vibrator and the full-wave,
self-rectifying one. Practically these units were used to convert
6 V DC to hight voltage DC.
In the beginning the due to its size and high efficiency, the synchronous
vibrator with an incorporated rectifier valve was the most often
Therefore in order to overcome some difficulties found during the
unit operation, since 1932 the vibrator was supplied with a separted
rectifier valve. Fig 317
Originally the first valves developed in the USA to be used with
vibrator for automobile application were mercury vapour half wave
rectifiers which were soon replaced by the high vacuum full wave
Since then, the power supply-using vibrator was adopted all over
the world up 1960 with the lauching in the market of the first solid-state