Opto input from 2v to 400v

John Bond

Hi Guys

Does anyone have a diagram for an opto input circuit for a BS2 which switches at not more than about 2.5 volt and can handle a continuous input of up to 400 volt. It would be useful if it also had an LED to·indicate input status. I have +5v regulated and +12v unregulated on the board.

I'm tired of smelling the acrid whiff of blown Optos, transistors and zeners.

Thanks a lot and kind regards from Kwa Dukuza

John Bond

ps. My response may be·erratic because we're experiencing telecom (telekom, Telkom, phone)·problems.
·

Jon Williams

That is an ENORMOUS range ... 2.5v to 400v. is that normal? Or are you getting surges that are popping components?

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Jon Williams
Applications Engineer, Parallax
Dallas, TX· USA

Alan Bradford

What voltage does the Optoisolator need to trigger at?

If it is not signal noise you are worred about then:

If it is 2.5 volts, then why the need for 400 volts?

If it is 400 Volts, then why the need for 2.5 Volts?

If you need to monitor a level from 2.5 Volts to 400 Volts then use a voltage divider and an A-D converter.

I use this method to monitor Plasma Cutting Torches from 0 volts to over 400 volts with a Stamp.

Then you can set the trip point in software, and vary it if necessary.

Hope this helps you out,

Alann Bradford

Plasma Technologies