[Boatanchors] 0Z4 Rectifier

[Carl]

I would suspect that the 0Z4 was initially developed for farm radios where 
the filament draw of a 84/6Z4 helped to deplete the 6V battery. That had to 
be regularly charged in the families vehicle or from a windmill charger. The 
6Z4/84 and the 0Z4 came out in 1935 and the 6X5 followed a year later. With 
all of the 6X5 internal troubles it wasnt used in auto radios until many 
years later.

In 1935 auto radios were still an expensive novelty option and seldom 
ordered, even in high end models, in the middle of the Depression. Reception 
was poor with antennas under the running board or buried in the cloth roof 
insert. The cowl mounted whip antenna was still a year or two away. OTOH, 
just about every home had a radio and once outside of the cities Rural 
Electrification hadnt taken root yet.

With the typical 25A generator charging system the 600ma savings was a minor 
help but not that critical unless you were parked with the engine off (-;

Carl
KM1H



>
> ================
>
>
>> The high forward voltage required to fire no doubt explains why they were
>> only used in vibrator supplies.
>>
>> In a message dated 5/19/2010 9:04:28 PM Central Daylight Time, 
>> al at ar88.net
>> writes:
>>> I had to dig to find any info at all on this subject.  Fred Terman in
>>> the 1943 edition of "The Radio Enginee's Handbooks" says, " Such
>>> rectifiers are used to a limited extent in connection with vibrator
>>> power supplies.  They have the advantageof needing no filament heating
>>> power, but require a relatively high voltage drop to start the flow of
>>> current, and introduce high-frequency transients."
>>>
>>> Checking the data sheet, one finds they need 300 volts to fire, and
>>> there is a requirement to maintain a 30 mA current flow.  I'm guessing
>>> they aren't particularly efficient when sine waves are applied, as they
>>> wouldn't fire until late in the cycle.
>>>
>>> BTW, a 6X5 or 6X4 rectifier only draws 450 mA for the heaters.
>>>
>>> Al
>>>
>>> On 5/19/2010 12:03 AM, mac wrote:
>>> >Saved a couple of amps of filament current.  Significant back in the
>>> >days of 6 volt electrical systems.
>>> >
>>> >Dennis D. W7QHO
>>> >Glendale, CA
>>> >
>>> >
>>> >
>>> >On May 18, 2010, at 9:41 AM, Jim Haynes wrote:
>>> >
>>> >
>>> >>I've wondered from time to time why the 0Z4 rectifier was used in,
>>> >>and used only in, automotive radios with vibrator power
>>> supplies.......
>>>
>>
>> Robert & Susan Downs - Houston
>> wa5cab dot com (Web Store)
>> MVPA 9480
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