Most sensors need some kind of amplification, isolation, filtering, or buffering between them and an ADC.
Data-acquisition systems let you digitize analog signals—often from sensors—after which you can collect, store, and analyze data or use the measurements to initiate actions. But, signals from sensors are often too small for direct connections to an ADC (analog-to-digital converter). Not only can signals levels be too low, but the signals need some combination of buffering, isolation, or filtering to get them ready for digitizing. That's called signal conditioning.
This week's questions are based on Signal Conditioning & PC-Based Data Acquisition Handbook, originally published by IOtech, now by Measurement Computing. As always, answers appear on the last page.
1. Often, the signal amplitudes you need to measure exceed the voltage range of your equipment. While adding a resistive voltage divider seems like an easy way to reduce a signal's amplitude, it can cause problems. Which problem or problems are most likely to arise from using resistive voltage dividers?
- Voltage dividers present low source impedances to the signal source.
- Voltage dividers can't sufficiently drop very high voltage low enough to measure.
- Voltage dividers present high source impedances to multiplexer inputs.
- Voltage dividers can almost can never reduce a source voltage accurately enough to be useful.
- a and b only
- a and c only
- b and d only
- c and d only
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