Products suited to this guided test*
  • Coil On Plug (COP) and Signal Probe

  • *At Pico we are always looking to improve our products. The tool used in this guided test may have been superseded and the product above is our latest version used to diagnose the fault documented in this case study.

Non-intrusive touch measurements using the COP and Signal Probe



The information on this page is illustrative. It is not to be used for training purposes or as guidance or instruction. It is also incomplete. A full version of this content can be found in our PicoScope 7 Automotive software, which is downloadable from here.



The purpose of the test is to confirm the operation of high-frequency and fast switching components within Electric Vehicle (EV) and hybrid systems using non-intrusive Coil On Plug (COP) and Signal Probe measurements.

COP and Signal Probe measurements.

COP and Signal Probe measurements.

Further information

In the example above, the COP Signal Probe detects the oscillating AC current (charge) in the circuit between the EVSE and the On Board Charger (OBC), before it is rectified to the DC voltage and current used to recharge the High Voltage (HV) battery. As such, the COP and Signal Probe can provide a safe and convenient quick check method for confirming the delivery of charge from the EVSE to the vehicle.

The COP and Signal Probe can be used to confirm the presence of activity in other circuits with high frequency or switching voltage characteristics.

When measured with the COP and Signal Probe, the absence of the waveform does not confirm that a voltage or current is not present (it might be that the components or cabling are so well shielded that the probe is unable to detect them); the COP and Signal Probes can only be used to confirm that a voltage or current is present.

The COP and Signal Probe cannot detect constant DC voltages or currents, whether they are within HV components or otherwise.

Always ensure that the COP and Signal Probe and its connection lead are not used in the presence of exposed HV circuits, components or systems and are kept clear from rotating components (whether moving or not).


This help topic is subject to changes without notification. The information within is carefully checked and considered to be correct. This information is an example of our investigations and findings and is not a definitive procedure. Pico Technology accepts no responsibility for inaccuracies. Each vehicle may be different and require unique test settings.

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Guided test: Non-intrusive touch measurements