2 ms·
measure the current, e.g. an ampmeter in series; voltage in parellel. W=V.I Most of the time you care about the current only. Now if you actually want power ov
by xxs 4y ago
measure the current, e.g. an ampmeter in series; voltage in parellel. W=V.I
Most of the time you care about the current only. Now if you actually want power over time, that is energy. in that case you would need some logging, and sampling
- ilyt 4y agoThe sampling is the problem here. If you sample at say 1s and the chip is using say 100mA for 50ms to send some data, you might completely miss it, you might overcount that pulse
- xxs 4y agowell yeah, of course, if you care about transients, you may switch to an oscilloscope. Alternatively have a multiplemeter that records min/max, and/or has a rs-232 interface. However with enough sampling, even 1Hz frequency should be sufficient.
- ilyt 4y agoOscilloscopes also have a dead-time. If you want to judge the power usage accurately you pretty much have to go to dedicated stuff like https://www.joulescope.com/ https://www.joulescope.com/ althought you might get close enough with using some tricks. Or the ye olde analogue way of integrating the current usage via Like, if you know your device is on 50ms and off 10 seconds you can just record both states power usage and calculate based on ratio, most scopes memory is probably enough for 50ms with enough resolution and idle power usage will most likely be the same over the period. > Alternatively have a multiplemeter that records min/max, and/or has a rs-232 interface. Min/max ain't going to do you much, some WIFI-enabled devices can spike to like 500mA for few us so even if it captures it the max doesn't tell you much.