Re: Basic Circuit Question
- From: Jasen Betts <jasen-b@xxxxxxxxxxxxxxxxxx>
- Date: Sun, 30 Oct 2005 13:47:48 +1300
On 2005-10-28, faceman28208@xxxxxxxxx <faceman28208@xxxxxxxxx> wrote:
> I am trying to debug a kit that I bought that isn't working. I am
> trying to test various links on the board with a an LED and resistor
> soldered together.
>
> When I hit the put the ends of the LED/resistor at a point on the board
> with a direct link to the power supply, it lights up (so the obvious
> isn't a problem).
>
> If I move my LED/resistor pair to the next in the chain, a diode I get:
>
> (-V9) ------- (- Diode +) ---- (- LED + ) --- (Resistor) --- (+9V)
>
> and the LED no longer lights. Should I expect it to light up,
> suggesting there is a problem with the Diode? Or is there something
> more to diode that I am unaware of (I just thought they were one-way
> current blockers -- suggesting the above should work).
>
> The Diode is a TN4001. Resistor is 267Ohm. Foward voltage on the LED is
> 3.7.
I'm guessing that you've got either the diode or the battery in backwatds,
for the LED to light the banded end should be towards the negative battery
terminal.
if the diode is between the battery and the rest of the circuit to protect
the circuit from a reversed battery then either it or the battery are
reversed.
if so it may be faulty or the faullt may lie elsewhere.
if not it may be behaving correctly.
Bye.
Jasen
.
- References:
- Basic Circuit Question
- From: faceman28208
- Basic Circuit Question
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