Hello everyone!
This is my first post here and hopefully I've placed this in the correct spot.
I've been watching Dave's videos and learning quite a bit. The #204 on designing a battery gauge with the LM3914 was particularly interesting.
I modified the circuit (or attempted to) to give me a range of 4.00v - 5.25v, keeping the range of 1.25v for simplicity sake. I calculated R1 as 13.04K and R2 as 14.55K. Since I'm using a low voltage, I'm not using a voltage divider. I've attached my circuit in a quickly-drawn mspaint image.
With a voltage of 5.09V and pin 9 floating, the LED on pin 10 lit. As I decrease the voltage, LED pin 11 lights, until I get down to around 3.4 volts and LEDs on pins 14,13,12,11,10 are lit. With pin 9 floating, it's supposed to be in DOT mode.
R1 and R2 are variable resistors and I've adjusted each to try to change the behaviour of the circuit, but haven't had any luck.
I've replaced every component, tried different LM3914s (I have LM3914N-1), different batteries. I'm missing something basic I think. Is it how I have removed the voltage divider?
Any help you can give would be most appreciated. I'm scratching my head and trying to get this to work.
Thanks!
john