Switching 100 VDC from the output of the stamp.
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I have a problem that I hope that someone can help me with. I need
to switch 110VDC once I come out of the stamp. Originally I just
bought NPN transistors and used opto-isolators with NPN outputs to
drive relays in a logic circuit.Worked great! Upon closer review I
needed to source the 110VDC to turn on the relays in the logic
circuit. PNP's will not work because of the high voltage that I need
to turn off the transistor. My opto-isolators will not handle the high
voltage. Are minature relays my only way out. Was hoping to do it on
the cheap I have 10 outputs that I need to control.
Thanks in advance,
Riooso
to switch 110VDC once I come out of the stamp. Originally I just
bought NPN transistors and used opto-isolators with NPN outputs to
drive relays in a logic circuit.Worked great! Upon closer review I
needed to source the 110VDC to turn on the relays in the logic
circuit. PNP's will not work because of the high voltage that I need
to turn off the transistor. My opto-isolators will not handle the high
voltage. Are minature relays my only way out. Was hoping to do it on
the cheap I have 10 outputs that I need to control.
Thanks in advance,
Riooso
Comments
>to switch 110VDC once I come out of the stamp. Originally I just
>bought NPN transistors and used opto-isolators with NPN outputs to
>drive relays in a logic circuit.Worked great! Upon closer review I
>needed to source the 110VDC to turn on the relays in the logic
>circuit. PNP's will not work because of the high voltage that I need
>to turn off the transistor. My opto-isolators will not handle the high
>voltage. Are minature relays my only way out. Was hoping to do it on
>the cheap I have 10 outputs that I need to control.
>
>Thanks in advance,
>Riooso
Riooso,
You did not say how much current at 110VDC you are trying to
switch, this is very important !!!!! It sound to me as though
once you
determine your current requirements you may still be able to use
your opto-isolator to drive an appropriate NPN TRANSISTOR rather
than driving a relay. Simply connect the opto-NPN output with
an NPN transistor, capable of handling your current/voltage demands,
in a darlington transistor configuration.
o
>+110VDC Source
|
|
Opto-Collector >
o
< NPN-Collector
Opto-Emitter >----o
< NPN-Base
|
o--/\/\
o
< NPN-Emitter
100K |
(Bias Resistor) |
o--[noparse][[/noparse]LOAD]-->GND (-110VDC Source)
Note: A good rule of thumb - Select a transistor that can handle
at least
twice the amount of current you require and at least 1.5
times the
voltage you require.
-Beau Schwabe