I have built a 12v high current power supply. I'm trying to use a Jewell Modutec BL series meter to display the current that the power supply is being loaded with. The meter's specs is that 200mV = 2000 and 0mV = 0000 respectively (the decimal may be placed by jumper).
I'm using a .03 ohm 250 watt resistor as a shunt. I want to have the meter read from 0A - 50A. Passing 50A through a .03 ohm resistor gives me 1500mV voltage drop.
I need to scale this 1500mV down to 50mV. Basically, here are my scales that I need to come up with.
0A - 0mV
50A - 50mV
These voltages will be fed into the meter for the display.
I've though about using a inverting amp with a 741 and cut the gain down by 30x. This would give me 50mV on the output of the amp when 1500mV is being fed into the input.
Would this work? The polarity would become reversed when using the inverting format but using a non-inverting format results in a +1 on the gain and throws my scaling off.
Am I over thinking this?
I'm using a .03 ohm 250 watt resistor as a shunt. I want to have the meter read from 0A - 50A. Passing 50A through a .03 ohm resistor gives me 1500mV voltage drop.
I need to scale this 1500mV down to 50mV. Basically, here are my scales that I need to come up with.
0A - 0mV
50A - 50mV
These voltages will be fed into the meter for the display.
I've though about using a inverting amp with a 741 and cut the gain down by 30x. This would give me 50mV on the output of the amp when 1500mV is being fed into the input.
Would this work? The polarity would become reversed when using the inverting format but using a non-inverting format results in a +1 on the gain and throws my scaling off.
Am I over thinking this?
