Do they make these for 0.05 amps?
Do they make these for 0.05 amps?
gee... another "ha ha ha" moment for my odd joke...Do they make these for 0.05 amps?
Yes, that would work.In the shunt circuit could you use a diode and solid state relay (spst nc or double it up, dpst) and not need the fuse?
Relay contacts in series with the hot lead.
Diode activates relay when voltage is reversed. Opens relay contacts.
That would have a low series resistance and hopefully be as fast as a fuse.
A DC solid state relay has a small forward drop from its internal MOSFET switch. I see no advantage of that over just using a MOSFET, and the SSR will be much more expensive.In the shunt circuit could you use a diode and solid state relay (spst nc or double it up, dpst) and not need the fuse?
Relay contacts in series with the hot lead.
Diode activates relay when voltage is reversed. Opens relay contacts.
That would have a low series resistance and hopefully be as fast as a fuse.
I'm using the circuit you posted back in #4Mike, I don't understand why you have two resistors to the gate. That's only required if the supply voltage is more than Vgs max. You just need one resistor to ground which will increase the Vgs and reduce the ON resistance.
If concerned about transients you can connect a 10V zener from the source to the gate.
Zapper
Are they not the same thing???I think somehow we spun off to transient protection from reverse power protection for a little power supply.
I was too lazy to point that out.No, I don't think so. He's looking for something to keep him from burning out his 1 amp boost converter if he hooks it up backwards to his 9 volt power supply. Your trying to protect something in a car or plane with all different types of possible transients and instantaneous reversals.
You may have used my circuit but you didn't read my description of the circuit. It stated that for voltages less then Vgs max. you didn't need the resistor between source and gate.I'm using the circuit you posted back in #4
The resistor to ground (with or without a Zener) will have the same problem turning off the PFET that I already explained in post #46.
Exactly.I think somehow we spun off to transient protection from reverse power protection for a little power supply.
You miss the point: if the circuit cannot protect from any and all possible (however unlikely) power faults for some other very expensive high current unit connected to a different power source then it is completely inadequate....He's looking for something to keep him from burning out his 1 amp boost converter if he hooks it up backwards to his 9 volt power supply. Your trying to protect something in a car or plane with all different types of possible transients and instantaneous reversals.
A Shottky diode is much faster than a regular silicon one, and clamps any reverse potential to a lower value as well.Keep it civil. This is not an option.
Keep it simple. Whatever happened to KISS, a quick blow fuse and a diode. For added protection you could always add a transistor, since they tend to beat the fuses when blowing out anyhow.
Best method for reverse polarity protection and without power loss?
From this I take away minimum power loss and reverse protection. Maybe battery operated.For 9v power, is a 1A diode or Schottky diode (I assume is better for lower voltage drop) good enough?