When measuring peak drain voltage, a high scope bandwidth is crucial to ensuring highly accurate measurements. The graphic below illustrates how different scope bandwidths can result in highly ...

In the photos above, the measured voltage is 17kV. The spark gap width (i.e. the spark length) is measured as just under 5mm. If we apply the formula for a 5mm spark gap, we get 3 x 5mm = 15kV.

The LM331 is a great chip, designed by the legendary Bob Pease. Resolution and linearity are very good; better than you’re likely to get with a micro with internal A/D. Be sure to read his ...