Alt-BEAM Archive
Message #01159
To: Wilf Rigter Wilf.Rigter@powertech.bc.ca
From: Steven Bolt sbolt@xs4all.nl
Date: Tue, 2 Mar 1999 11:35:52 +0100 (CET)
Subject: [alt-beam] Re: pocket motor-tester / BEAM multi-meter
On Tue, 2 Mar 1999, Wilf Rigter wrote:
> Quote from the WILEY ENGINEER'S DESK REFERENCE
>
> Energy (W) stored in a capacitor C at potential V volts
>
> W=1/2CV*V in joules
Hmm... The C in the above isn't charge, but capacitance.
And capacitance = charge / voltage, which takes out the square.
> Anyway your early photovore modulates the output with a
> squarewave ie PWM, right?
No. The pulse generator gives a narrow (about 1ms) pulse at 5Hz (as
shown in the SunEater_II schematic on Brian's page). This has the
effect of putting the voltage trigger in the linear, high current
consumption mode only about 0.5% of the time, reducing Icc while
the storage cap is being charged. When the switch-on level is
reached, the pulse generator stops and the motor receives all
available current, until the switch-off level is reached and the
pulse generator restarts.
Best,
Steve
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# sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
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