1. Obtain a copy of the specification sheet that lists the standard current monitors. These monitors are able to measure pulses, transients and continuous signals. They do not measure steady-state dc current.
2. The first four columns of the specification sheet give model number, output sensitivity and physical dimension information. The next four columns list the specs that apply to measuring pulses, and are referred to as time domain parameters. The final four columns list the specs that apply to measuring continuous sine-wave currents and are referred to as frequency domain parameters.
3. Determine if the application is to measure a pulse or continuous signal. If the signal is more complex, and rms, peak, dc or other limiting values are hard to determine, refer to Pearson Electronics Application Notes, or call our engineering department.
4. If there are several monitors that satisfy the above criteria, a selection based on voltage output (sensitivity) and size can now be made. In the third column is given the output volts per primary amp to be measured. For example, a 1 milliamp signal will produce a 1 millivolt output for a monitor that has a 1 volt/amp output.
5. An often asked question concerns terminating the output of the monitor with a resistor. Since the monitor can be modeled as a voltage source in series with 50 ohms, the addition of an external terminating resistance will decrease the output of the unit. For example, a 50 ohm external termination would reduce the output to one-half.