To make a long story short, I'm trying to replace a small LED built in to a circuit board with an external LED indicator light. It works fine with the LED receiving 3.8VDC when it's supposed to be on. The problem is when the LEDs are off they still receive 1.8VDC. I've tried both 2.2Vf and 5Ff 5mm bare LEDs with the same results - they still glow dimly when they're supposed to be off.
I understand basic electricity but not a lot of the IC stuff. It sounds like I either need to find a LED that will turn on with 3.8V but not with 1.8V, or use a resistor to lower the voltage to achieve the same affect. However, the descriptions I've read of zener diodes and/or shunt regulators sound like they are exactly what I want.
If I get a zener diode/shunt regulator with a rating of 3.3V, will it turn off the LED completely with the 1.8V current and turn it on with 3.3V or 3.8V when it sees the 3.8V current?
Is there an easier way to do this? What's the difference between a shunt regulator and a zener diode? I have 5 LEDs (4 green, 1 amber). If you can provide part numbers and sources plus wiring instructions I would be grateful.
Allen
I understand basic electricity but not a lot of the IC stuff. It sounds like I either need to find a LED that will turn on with 3.8V but not with 1.8V, or use a resistor to lower the voltage to achieve the same affect. However, the descriptions I've read of zener diodes and/or shunt regulators sound like they are exactly what I want.
If I get a zener diode/shunt regulator with a rating of 3.3V, will it turn off the LED completely with the 1.8V current and turn it on with 3.3V or 3.8V when it sees the 3.8V current?
Is there an easier way to do this? What's the difference between a shunt regulator and a zener diode? I have 5 LEDs (4 green, 1 amber). If you can provide part numbers and sources plus wiring instructions I would be grateful.
Allen