Another term like "inrush current"?
prof_braino
Posts: 4,313
Is there another term similar to "in-rush current"? Except not when the circuit is switched on, its after all the parts are running but then all start drawing higher current.
I've run across a situation where I have a wall that is rated (I think) to be sufficient for the load. (7.2 volts at 1000 mA, standard parallax wall wart).
I have a prop protoboard, a bare prop chip (connected by 7 wires to the protoboard which is emulating EEPROM and handling communications), and a spinneret.
And everything works fine most of the time.
I think it should draw (75mA +75mA + 175mA)
However, sometimes the spinneret has issues. It seems using the Ethernet and writing the EEPROM at the same time (or similar) is just enough to cause something to not work.
The suspicion is that the wall wart can't respond quickly enough to an abrupt change in draw, when a bunch of cogs and the EEPROM and the wiznet all start dancing at once.
This hypothesis is supported, by putting a separate wall wart on the spinneret, the issue goes away.
Anybody else see this? What the term for this? (Aside from "operator error").
I've run across a situation where I have a wall that is rated (I think) to be sufficient for the load. (7.2 volts at 1000 mA, standard parallax wall wart).
I have a prop protoboard, a bare prop chip (connected by 7 wires to the protoboard which is emulating EEPROM and handling communications), and a spinneret.
And everything works fine most of the time.
I think it should draw (75mA +75mA + 175mA)
However, sometimes the spinneret has issues. It seems using the Ethernet and writing the EEPROM at the same time (or similar) is just enough to cause something to not work.
The suspicion is that the wall wart can't respond quickly enough to an abrupt change in draw, when a bunch of cogs and the EEPROM and the wiznet all start dancing at once.
This hypothesis is supported, by putting a separate wall wart on the spinneret, the issue goes away.
Anybody else see this? What the term for this? (Aside from "operator error").
Comments
-Phil
Take for example a GPRS modem. It might draw an average of 100mA, but during the transmission it draws pulses of current in th 1.52.5A range. If is not up to it, those peaks will cause corresponding voltage sags and possibly activate the brownout detectors or simply go haywire. Add up the possibily overlap of peaks from different souces.
With power adapters, there is a voltage drop along the wire from wall to workplace. Thus a big capactor is called for right where the current is needed.
Duane J