Measurement Specialties CIO-SSH16 user manual Analog Electronics, Voltage Dividers

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6.0 ANALOG ELECTRONICS

This short introduction to the analog electronics most often needed by data acquisition board users describes the following:

Voltage dividers.

Differential vs. Single Ended Inputs. Isolation vs. Common Mode Range

Low pass filters for analog and digital inputs. A/D Resolution

Conversion to Engineering units.

4-20 mA inputs

ONoise; sources and solutions. Digital interfacing.

Each deals with the impact on measurements made with data acquisition boards. For additional information on the subject of data converters and analog electronics, Radio Shack has written an excellent Op Amp handbook and has an Op Amp experimenters kit.

A more advanced treatment is in the Analog-Digital Conversion Handbook (32.95) and the Transducer Interfacing Handbook ($14.50) published by Prentice-Hall.

6.1 VOLTAGE DIVIDERS

If you wish to measure a signal which varies over a range greater than the input range of an analog or digital input, a voltage divider will drop the voltage of the input signal to the safe level the analog or digital input can measure.

A voltage divider takes advantage of Ohm's law, which states, Voltage = Current * Resistance

and Kirkoff's voltage law which states,

The sum of the voltage drops around a circuit will be equal to the voltage drop for the entire circuit.

Thus, any variation in the voltage drop for the circuit as a whole will have a proportional variation in all the voltage drops in the circuit (Figure 6-1).

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Contents CIO-SSH16 Copyright 2000 Measurement Computing Corp Adding Amplifiers & Sample / Hold Chips This page is blank Introduction Software InstallationHardware Installation Power Cable Signal Cable Power ConnectorAnalog Input Board Setup Gain SwitchesSignal Connection Connector DiagramAnalog Inputs Floating DifferentialDifferential ExamplePage Amplification ArchitectureAnalog Input CIO-SSH16 vs. Programmable Gain A/D Boards Sample & Hold S15 S16 Sample and Hold Timing Diagram Droop RateResolution Calculation Adding Amplifiers Sample / Hold ChipsRange Calculation Time to Sample CalculationSpecifications Analog input sectionSample / hold section Analog Electronics Voltage DividersPage Common Mode Range Differential & Single Ended InputsPage LOW Pass Filters Common MisunderstandingsGround Loops A/D Resolution & Engineering Units Converter # VoltsEngineering Units Current Loop 4-20 mANoise Sources of NoiseSignal Wire Noise Sensor NoiseSmoothing Data For your notes EC Declaration of Conformity