0Z4

How would one go about making a solid state substitute for this rectifier tube, so that it could function with a vibrator in a car radio?

My understanding is, just placing diodes won't work with a vibrator.

I dont agree with Your pessimism: I think that diodes would in fact do the job. They are rather unlimited compared with the restriction of a gas discharge rectifier. A gas rectifier needs a starter supply voltage, here it is specified with 300 volts per plate. Furthermore a minimum current is necessary to maintain the "arc". Here 30 ma DC output current is the specified minimum.

Diodes are free of all such limitations. Only max. current and peak inverse voltage have to be considered, thats all. Maybe a few hundred ohms in series to protect the vibrator contacts are advisable. 1N4007 or similar should be sufficient.
Have a try.

Good luck,
KoBi

I appreciate and honor the theoretical considerations. But I think that the max.30µs of a diode (per specification) are short enough to limit the dangerous energy transfer during the transient phase to a bearable amount. And there is a choice of alternatives in the diodes sector. Only the 1N400x series are amongst the cheapest. 

In the post war time numerous mechanical vibrators worked in combination with selenium rectifiers, which are not really fast switching devices.

And theoretically synchronous (self rectifying) vibrators should have never been used at all. There are phase shift problems between Xformer primary and secondary, which to a certain amount apply to our substitution as well. 

The a.m. series resistors to the diodes are a must of course.

Hi,

what you ment as a snubbing cap, if seen parallel to a diode or bridge in a radio device has an other purpose. It is to short the HF to ground, otherwise you modulate your HF signals with the mains ferquency, because the device is periodically less or more connected to ground. Especially on transmitters power supply, but also on receivers.

Georg Beckmann

Dear Omer,
don't apply such caps. They would in contrary slow down and expose the diodes to an additionally stored charge which then would load the diodes. To suppress RF interference by harmonics blocking the +B and /or across the secondaries may be more advisable. Since such phenomena depend from many circumstances (grounding / wiring) an experimental solution ist often the better way.

 If You would feel safer, spend a few cent more and buy power Schottky or Avalanche diodes. They are fast switching.

Dont worry about the poor little vibrator contacts. They have anyway to deal with changing reactive load conditions, where current and voltage are not in phase. That means certain arcing is practically unavoidable.

By the way: To my understanding the 1N400x series diodes are neither designed for nor limited to 60 Hz sine wave rectification. They are found in multiple applications e.g. in TV sets. Of course not in high frequency circuits.

Anyway: Good luck!

Attachments

• DATA_OZ4 (115 KB)