Print Page - Delay between input and analogue output

Title: Delay between input and analogue output
Post by: pete_dl on July 28, 2022, 12:08:49 PM

Hi,

I am trying to measure the power draw of a low voltage AC signal. I am using the output of the Current Ranger on one input to a scope and measuring the voltage on a differential probe on another scope input.

I am getting some unusual results, so need to check that the delay through the Current Ranger or the differential probe is not introducing a significant phase difference. The AC signal is only 20hz, so if the Current Ranger delay is on the scale of microseconds, I can ignore it.

I would be grateful for a rough estimate of the delay.

Thanks,
Peter.

Title: Re: Delay between input and analogue output
Post by: Felix on July 28, 2022, 05:27:51 PM

At that low frequency I would look elsewhere. The CurrentRanger bandwidth is far above that to worry about any propagation delays.
Just make sure your input current is not overloading the CR's opamps, which can take a significant time to recover from the overload condition 4-6ms, see datasheet (https://www.mouser.com/datasheet/2/256/MAX4238_MAX4239-1307777.pdf).
Also look at the slew rate, but that again is so fast rising that at 20hz its irrelevant.

Title: Re: Delay between input and analogue output
Post by: pete_dl on July 29, 2022, 04:48:30 AM

Thanks. This information will aid my debugging.

Pete.

LowPowerLab Forum

Hardware support => CurrentRanger => Topic started by: pete_dl on July 28, 2022, 12:08:49 PM