How to measure drive current with an oscilloscope and current probe connection

In this example, a Tektronix CT-6 probe was used to measure the drive current. When placing the current probe, special attention should be given to the orientation. For inverter type oscillators, the drive current should be measured on the output side of the crystal in order to contain the influence of the oscillator. See Figure 1. Oscilloscopes measure voltage versus time, though the display value is in mV, the current probe converts the electric field to AC current. The voltage can be ignored; in reality it is current. Oscilloscopes can display AC current in peak, peak to peak, or RMS. For most cases, we can assume the waveform is a pure sine-wave. See Equation 1 and Figure 2. Refer to AN-830 for more details. For other questions not addressed by the Knowledge Base, please submit a technical support request.

 

 

                                                               

 

Documents

Title Other Languages Type Format File Size Date
Application Notes & White Papers
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 4, 2014