I am looking to create an analogue dc voltmeter as a item of test equipment be used to fine tune a mechanical linkage (attached to a pot) to achieve exactly 2.5v. Hence I would like 2.5vdc at the centre point and simple instructions to adjust left on adjust right on either side. The ideal would be approx 1.5vdc at the min point, 2.5vdc at Centre and approx 3.5vdc at the max , i.e. giving a relatively fine reading of values deviating either side of the critical value of 2.5v.
I had thought this would be easy (even with my limited electronic skills) using an off the shelf analogue multimeter with a 2.5vdc option (not quite the resolution I ideally wanted but close enough). I set about soldering a voltage divider with the intention of halving the signal voltage the hence achieving 2.5v signal = actual reading 1.25v = needle at centre. The problem here is, having tried various resistor values the divider circuit appears to pull down the supply voltage. It is obviously essential that the measuring device does not affect the supply voltage.
My questions therefore are:
Is there perhaps a neater and cleverer way of achieving this with some form a comparator chip based circuit perhaps driving Led's?
Is there any way specifying the optimum resister spec for such a divider?
Are diodes my answer, in which case how do I integrate and or spec the right component?
Any advice gratefully received.
I had thought this would be easy (even with my limited electronic skills) using an off the shelf analogue multimeter with a 2.5vdc option (not quite the resolution I ideally wanted but close enough). I set about soldering a voltage divider with the intention of halving the signal voltage the hence achieving 2.5v signal = actual reading 1.25v = needle at centre. The problem here is, having tried various resistor values the divider circuit appears to pull down the supply voltage. It is obviously essential that the measuring device does not affect the supply voltage.
My questions therefore are:
Is there perhaps a neater and cleverer way of achieving this with some form a comparator chip based circuit perhaps driving Led's?
Is there any way specifying the optimum resister spec for such a divider?
Are diodes my answer, in which case how do I integrate and or spec the right component?
Any advice gratefully received.