ljcox
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I initially did the design using MOSFETs but I needed 2 protection diodes per MOSFET which means 160 diodes.
Are you sure?Whereas, relay contacts don't need protection.
2 diodes plus a mosfet is WAAAAAY cheaper than any relay you'll find.Klaus,
Thanks for the response. I tried the manufacturer's web site did not think of looking for the distributors.
What I meant by "E14 have little to offer" is that although some were technically suitable, they were all too expensive. Remember that I need 80 relays
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Barry,
Thanks for the response.
I initially did the design using MOSFETs but I needed 2 protection diodes per MOSFET which means 160 diodes.
Whereas, relay contacts don't need protection.
Len
I need relays with the following specifications:-
A coil voltage in the range 5 Volt to 48 Volt.
Contacts - either DPST or DPDT able to switch at least 60 Volt DC and a current rating of at least 500 mA.
I prefer SMD mounting but through the hole will suffice if SMD relays with the above specifications are not available.
Does any one know where I can purchase such relays? I need 80, so the price is critical.
I tried RS Components & Element 14, but they have little to offer.
I also did a search of Chinese companies but found their web sites frustrating. The ones I viewed did not have a sensible search engine. Besides, I have the feeling they don't want enquiries from the likes of me.
Any assistance will be appreciated.
Len
Seeing this circuits, I don't understand why you consider a double throw relays or respective electronic switches. I only see a SPST switch function and a hold logic function that can be well implemented by means of switch control. Thus you are talking about a single floating 60V/500 mA switch, apparently unipolar plus respective control logic.I have attached the 2 of the options I have been considering.
I generally disagree. Both may work without or need protection circuitry, depending on the load and expectable maximum voltage.I initially did the design using MOSFETs but I needed 2 protection diodes per MOSFET which means 160 diodes.
Whereas, relay contacts don't need protection.
My fault, the circuit actually uses DPST rather than SPDT.FvM, Thanks for the response but I don't understand it.
What do you mean by"double throw relays" The circuit shows a DPST relay.
And in this sentence "I only see a SPST switch function and a hold logic function that can be well implemented by means of switch control" what do you mean by "switch control"
Um, your PIC is not going to be able to handle 500ma at 60 V. The inputs have 100k resistors in series to protect the PIC inputs. Looks like you're back to your original question. And it's not clear what's going on here. In your sketch in post #9 where's the load? The point is to apply a 0V to the P wire when necessary. You show a DPST relay shorted together making it SPST. No, it is a DPST - only the lever springs are connected together. And your diode to "prevent positive pulses" is paralleled by a resistor that will conduct positive pulses. Yes, but the resistor will be 100k also.
I think we need a better explanation of what you're trying to do here.
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