Tagged Questions

3
votes
2answers
134 views

ADC for measuring 0-5V but connected to 3.3V device

I have a BeagleBone (BB) and want to connect the analog output of a motor controller to it. The motor controller creates an output in the range of -4V to +4V and the BB anlog inputs only accept ...
2
votes
3answers
143 views

How do I calculate the input voltage based on an ADC reading?

+UB is a 12V power supply. I have to find the voltage on U_KL30. I take this U_KL30 as an input at PortA<1> of my MC9S08DZ60 and use an ADC to get a ...
4
votes
2answers
226 views

Floating voltage measurements

Is there a very cheap way to measure several voltage differences of 0.1V to 10V (to ~1% accuracy at 10Hz, say), where each pair of measurement terminals may be tens of volts away from the ground of ...
2
votes
1answer
200 views

Trying to understand prescaling voltage for ADC with least error

I'm teaching myself EE while designing a 12V DC battery monitor. I'm using a pair of Hall-effect sensors to track charge & load current and looking for the best way to measure the voltage. [An ...
6
votes
2answers
439 views

Arduino has an input value in disconnected pin

I'm new to arduino. Maybe is an elemental question... If I load this program: ...
-3
votes
1answer
146 views

Delta Sigma ADC

I need to measure an magnitude of an AC signal with a constant frequency. The problem is offset of the AC signal varies. What I am thinking is filtering the signal and than using Delta Sigma ADC to ...
5
votes
3answers
552 views

Instrumentation Amplifier - how to use it correctly

I am trying to perform some measurements based on a special technique used to detect corrosion in rebars of concrete bloc. The idea is to measure the potential difference between an electrode and the ...
1
vote
1answer
423 views

How can i measure voltages on each phases of a 3 phase system, Using a microcontoller?

How can i measure voltages on each phases of a 3 phase system. The measurement is to be processed by a microcontroller. Is there any special chips available, or do i need to use the ordinary ...
1
vote
3answers
472 views

Measuring voltage across a resistor using a micro controller

I want to measure voltage across a resistor using the ADC of a PIC micro controller. But my problem is that both ends of the resistor are above GND and may be above 5V. But the difference is always ...
1
vote
1answer
1k views

reading voltage using TI's MSP430 FF22x4

I am trying to measure a power device's voltage using TI's MSP430. The voltage source is connected to A1 (i.e. P4) and ground (i.e. P1) on the target board. Here is the relevant code: ...
7
votes
3answers
908 views

Auto-Ranging Meter Design

I'm designing an auto-ranging voltmeter using the on-board ADC of my micro for A to D and a digital potentiometer as a programmable resistive divider to control the range. My concern is the ...