); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY On Tue, 6 Nov 2007 13:52:13 -0500, Didier Juges <[EMAIL PROTECTED]> wrote:
>The problem with a mercury relay is that the switching delay is significant >and not well controlled, so the duty cycle of the resulting waveform is not >well controlled, and so would be the RMS value. Not at all. The early edition of the Berkeley Nucleonics precision pulser, capable of delivering a monotonic amplitude pulse to a 4096 multichannel analyzer, used a pair of off-the-shelf Claire MWRs, one to switch the reference voltage to a capacitor and another to switch the charge to the pulse forming network. In later models they changed to a complicated solid state circuitry that never was quite as stable. None of that is particularly relevant here because he needs a simple circuit to check the accuracy of a 6 bit ADC in a scope. The RMS value doesn't matter, as the output is a simple square wave that swings between 0 volts and precisely the value of the DC source. Neither does the frequency. The advantage of the reed relay approach, in addition to precision, is that the circuit can be thrown together on a bench using jumper clips in 5 minutes, assuming a MWR is on hand. A voltage source (battery even), a good DVM, the relay and a 6 volt filament transformer to drive the coil is all that is needed. More than good enough for a 6 bit application. -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Democracy is three wolves and one sheep voting on what to have for supper. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.