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-   -   Data requested for BAY83 diode (1969 vintage) (https://www.vintage-radio.net/forum/showthread.php?t=153317)

Robsradio 20th Jan 2019 10:16 pm

Data requested for BAY83 diode (1969 vintage)
 
Evening
I have a clock which is a 'kick rewind' type and has a solenoid coil with this BAY83 diode across it for back EMF quenching. The diode is short circuit and whilst I know any high voltage diode will perform in this role, does anybody have data on this diode please, the date code is wk20 1969.
Thanks in anticipation
Rob

Terry_VK5TM 20th Jan 2019 11:27 pm

Re: Data requested for BAY83 diode (1969 vintage)
 
While I can't dig up a datasheet at the moment, an article in VHF Comms magazine lists the 1n914/1N4148 as suitable substitutes for the BAY83, which will put it in the silicon 75v 100mA area (although I have seen a 300mA rating in a datasheet for 4148's recently).

Robsradio 21st Jan 2019 11:00 am

Re: Data requested for BAY83 diode (1969 vintage)
 
Thanks Terry, that was probably what I was going to use, but really wanted to know BAY83 voltage as it is used to quench back EMF from a coil on 24v dc, so I am not certain that 75v will be enough?

Terry_VK5TM 21st Jan 2019 1:23 pm

Re: Data requested for BAY83 diode (1969 vintage)
 
75v is more than enough.

The flyback voltage across a coil with a diode connected wont be any more than the forward voltage drop of the diode itself and then only for a matter of milliseconds.

If your still worried about it, use a 1N4004 or 1N4007.

Robsradio 21st Jan 2019 1:50 pm

Re: Data requested for BAY83 diode (1969 vintage)
 
Fair point, hadn't really thought about it in those terms, I got hung up on the open circuit potential, I will fit a 1N4148, and it also resembles the BAY83 so will look right too :-)

julie_m 21st Jan 2019 3:32 pm

Re: Data requested for BAY83 diode (1969 vintage)
 
The maximum reverse voltage across the anti-kickback diode will be equal to the "HT" rail of the circuit (since the diode is reverse-biased most of the time), and the maximum forward current through the diode will be equal to the operating current of the relay (since that is what was flowing at the moment before it was disconnected, and coils behave as though the electrons in them have inertia, so will try to maintain that current).


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