Hi there,
Complete neophyte to the electronics world, I've attempting to put the theory to work and a touch confused.
I'm using an Arduino to drive a gauge. The gauge is effectively a voltmeter with a maximum input of around .815V, as measured with a cheap meter. I slowly stepped up the voltage using PWM on the Arduino to get to that figure, stopping at 42 out of 255. Calculating the estimated output (42 / 255 * 5V), I get a slightly higher output of .823.
I'd like to have maximum control of the gauge. So, I'm thinking I should use a voltage divider to step down the max output of the Arduino (5V) to max at .82-ish, allowing me to use all 255 stops instead of just 42. I understand the basic math of the voltage divider, but I'm curious why I would use one set of resistors versus another.
Whether I use a 5k R1 and a 1k R2, or a 500/100 pair, the ratio remains the same. Given this gauge requires very little amperage, why would I use one pair or another?
Also, I'm thinking I should estimate a little aggressive with the final output V. If the circuit steps the 5V down too far, I won't reach the 100% mark on the gauge. Any thoughts on the voltage drop seen in the real world, would be helpful. As noted above, the theoretical 16% of the 5V put out by the Arduino is more like .815V of 4.93 max potential.
Thank you.
Complete neophyte to the electronics world, I've attempting to put the theory to work and a touch confused.
I'm using an Arduino to drive a gauge. The gauge is effectively a voltmeter with a maximum input of around .815V, as measured with a cheap meter. I slowly stepped up the voltage using PWM on the Arduino to get to that figure, stopping at 42 out of 255. Calculating the estimated output (42 / 255 * 5V), I get a slightly higher output of .823.
I'd like to have maximum control of the gauge. So, I'm thinking I should use a voltage divider to step down the max output of the Arduino (5V) to max at .82-ish, allowing me to use all 255 stops instead of just 42. I understand the basic math of the voltage divider, but I'm curious why I would use one set of resistors versus another.
Whether I use a 5k R1 and a 1k R2, or a 500/100 pair, the ratio remains the same. Given this gauge requires very little amperage, why would I use one pair or another?
Also, I'm thinking I should estimate a little aggressive with the final output V. If the circuit steps the 5V down too far, I won't reach the 100% mark on the gauge. Any thoughts on the voltage drop seen in the real world, would be helpful. As noted above, the theoretical 16% of the 5V put out by the Arduino is more like .815V of 4.93 max potential.
Thank you.