I've seen 95V but nothing as high as 125V. The high brightness ones are usually 95V
http://www.farnell.com/datasheets/57560.pdf -pete On Thu, Nov 16, 2017 at 6:38 AM, David C. Partridge < david.partri...@perdrix.co.uk> wrote: > In an earlier post I quoted the following description of the photo-chopper > circuit from the 419A manual > > 4-43. Assume that DS1 lights when the input is applied to T2. Capacitor > C1 charges until the oscillator switches the input, and DS1 goes off. > When > the oscillator switches again, the charge on C1 insures that DS2 fires, and > DS1 stays off. This cycle continues with DS1 and DS2 firing as long as > there is output from the oscillator. CR1 and CR2 prevent the capacitor > from > discharging through R1 and R2 > > That description also applies to the 3420B chopper. > > For this to work as described, George Einst says that the striking > characteristics on the neons are critical, which I totally believe given > what's happening in mine. > > AFAICT, *both* neons are striking on every +ve portion of the square wave > drive signal, so the flip-flop behaviour doesn't happen. > > I checked on the curve tracer, and both neons strike at almost exactly 70V. > Both are also totally clear which suggests to me that they are not the > originals. > > Does anyone have any idea how much the strike voltages would need to differ > for this to work, and does anyone have any suitable neons - the only ones I > have are these shorter ones and they strike at about 125V. > > These are the longer bodied neons (glass about 5/8" long). > > Thank you > Dave Partridge > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.