The PP179 and PP266 current clamps are ideal for use with a PicoScope automotive oscilloscope to display starter current waveforms, charging currents and for performing quick compression tests (see waveforms below).
The current clamp can measure up to 600 A (AC or DC). In use there is no need to break into the circuit or disturb the isolation as the opening jaws simply clamp around the current carrying conductor. No electrical contact is required.
The PP179 current clamp is supplied with 4mm (banana) plug type connectors so can not be plugged directly into the PicoScope. To connect to the PicoScope we recommend the use of the TA000 BNC to 4mm test lead, alternatively the MI078 BNC to 4mm plug adaptor can also be used.
The PP266 current clamp features a BNC connector and can be plugged directly into the PicoScope.
Once connected to the PicoScope, switch the current clamp on (green LED should light) and then clamp the jaws around the current carrying conductor as shown.
Using the PP179/PP266 Current Clamp with PicoScope Software
The current clamp is calibrated to provide 1 mV of output for every 1 Amp of measured current. A quick check that the clamp is working can be done by measuring the current drawn when a cars headlamps are switched on. To do this start PicoScope and select 100 mV range (DC coupled) on either the scope or the meter. Connect the clamp around the ground connection to the car battery. With nothing on the car switched on the reading on PicoScope should be near 0 mV. Now switch the headlamps on, the reading should jump up a few mV (1 mV per amp of current drawn.) If the reading in fact jumps down, don’t worry—current clamps are directional, just reverse the clamp on the conductor.
Using PicoScope it is easy to scale the output from the clamp from mV to Amps. First select Settings | Custom Ranges from the drop down menu and click on the ADD button.
Next fill in the scaling information as shown on the right. This simply scales from mV to Amps and provides a 0 to 600 A range (the maximum the clamp can measure). Other ranges can be added in a similar way, for example for a 0 to 100A range change each occurrence of the number 600 to 100. More information on scaling can be found in PicoScopes online manual.
When you have filled in the scaling information press the OK button (twice) to return to the main menu. Now select File | Save Settings to save your custom range. This custom range now appears in the drop down list of voltage ranges (see examples below.)