P
panfilero
- Jan 1, 1970
- 0
I was making a circuit that when you power it up with 5V a 5V LED indicatorturns on and if you power it up with 12V the 5V LED goes off and the 12V indicator goes on.
But... it's not coming on with 5V...
I spiced it, and it doesn't work in simulation either...
if you look at the image on the link
I put a 5.6V zener D1 in the circuit thinking that this Zener would be OFF until I provide it a voltage drop of 5.6V, and since it's in series with some other stuff (resistors and an LED) I thought it would definitely be off at 5V, but it's on just enough to turn on my FET M1 and not let my D4 LED light up... I'm basically measuring a little over 1V at the gate.
I think I can remedy this problem by changing R2 to a lower value... like 1k maybe, but why is D1 turning on at all? Is it leakage current that's causing this circuit not to work at 5V? D3 the 12V LED is definitely off at a5V supply (as it should be) and the circuit works at 12V... but not at 5V....
link is below
http://vampiresquidlabs.com/cms/temp/
much thanks!
But... it's not coming on with 5V...
I spiced it, and it doesn't work in simulation either...
if you look at the image on the link
I put a 5.6V zener D1 in the circuit thinking that this Zener would be OFF until I provide it a voltage drop of 5.6V, and since it's in series with some other stuff (resistors and an LED) I thought it would definitely be off at 5V, but it's on just enough to turn on my FET M1 and not let my D4 LED light up... I'm basically measuring a little over 1V at the gate.
I think I can remedy this problem by changing R2 to a lower value... like 1k maybe, but why is D1 turning on at all? Is it leakage current that's causing this circuit not to work at 5V? D3 the 12V LED is definitely off at a5V supply (as it should be) and the circuit works at 12V... but not at 5V....
link is below
http://vampiresquidlabs.com/cms/temp/
much thanks!