User manual

USB DrDAQ User's Guide 33
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Example 3: Measuring 10 volts
Notes:
This is a simple circuit that uses a
potential divider to reduce the voltage
going into the USB DrDAQ by four. R1
= 3k & R2 = 1k The resistors are
calculated using Ohm's Law, V=IR.
Auto-Detect
Auto-detect resistor is placed between Ground (Pin 2) and
Signal Detect (Pin 3). The value of the resistor should be
selected from one of the following common values: 1k0, 2k2,
3k3, 5k6, 7k5, 10k. It is necessary to have an auto-detect
resistor so that the software can automatically scale the input
signal into the property that it represents.