Drawing voltage of a circuit in parallel

AI Thread Summary
The discussion revolves around issues with combining two circuits powered by a proximity probe, where one circuit displays voltage directly and the other requires a 5:1 voltage step-down for a programmable chip. The main problem identified was insufficient current capacity from the voltage source, leading to voltage drops when both circuits were connected. Suggestions included measuring the current draw of each circuit and testing the voltage source with a resistor to assess voltage drop under load. The importance of using appropriate methods for stepping down voltage, particularly avoiding voltage dividers for DC, was also highlighted. Ultimately, the issue was resolved by increasing the resistor values, eliminating the voltage drop.
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I have created a 2 circuits, that run off a voltage produced from a proximity probe (they have their own power suplies), one that takes the voltage straight off and then outputs the voltage on a digital display, and one that needs to be stepped down in the ratio 5:1 so that the voltage can be fed into a programmable chip which gives differnet outputs for differnet voltages. each of the circuits works fine on their own, but i cannot combine the circuits so that i can have both running at the same time. how should i set this up, as my parallel circuit does not seem to work as it lowers the voltages.

thanks
 
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How much of a voltage drop did you get? It sounds like your voltage source does not have enough current capacity to run both circuits.

As a test, can you measure (or estimate) the current used by each circuit separately? Then test the voltage source by using an appropriate sized resistor (that would draw the combined current of the two circuits) and see how much voltage drop you get.

Make sure the resistor exceeds the power requirement.

Another question: how are you stepping down the voltage? Is this AC or DC? Hopefully you are not using a voltage divider to step down a DC voltage, but if you are then that is the problem.
 
More questions about your circuits:

Is your proximity probe source actually powering the two circuits, or do the circuits have separate power supplies and they are only there to measure the voltage out of the probe?

What is the voltage, both open-circuit and under load? AC or DC?
 
thanks for the help, i solved the problem by massivly uping the resistor values that i measured the power off, therefore meaning that i was not getting a voltage drop anymore
 
You're welcome, glad you were able to make it work.
 
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