Vernier Tech Info Library TIL #640

Question

I am performing an experiment that requires both positive and negative voltages to be measured. When using your ULI with a Voltage Probe, it only reads 0 to 5 volts. What can I do to measure both positive and negative voltages?

Answer

The problem is that the ULI, or SBI, can only read positive voltages. Listed below are several options to read both positive and negative voltages:

A) Use our Instrumentation Amplifier (takes +/- voltages and amplifies them so that they can be read by the ULI (voltage ranges include +/- 20 mv, +/- 200 mv, +/- 1000 mv.
B) Use our Current and Voltage Probe System. The voltage range using this is +/- 6V.
C) Put a battery in series with the voltage probe of the ULI to offset the voltage you are measuring by 1.5 volts.
D) Build a simple op-amp circuit to handle the input and feed it to the ULI voltage leads.
E) Use our Go! Link or LabPro interface with a voltage probe. Both of the newer interfaces have a range of +/- 10V.

Created by: dvernier on January 03 2000
Last updated by: jhopkins on July 06 2004