Look at the Jim Williams application note <http://cds.linear.com/docs/en/application-note/an47fa.pdf>
Regards, David Partridge -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ct1dmk Sent: 26 December 2013 16:08 To: Discussion of precise time and frequency measurement Subject: [time-nuts] fast edge, rise time. Hello, I'm willing to generate a pulse (of some few hundred volts) by discharging a capacitor into a pulse transformer I'm solely interested is the active edge (call it either rise or fall depending on the wiring of the output of the transformer). The target is 4ns, while ideas seemed to be clear at some point, now I'm having doubts if better to use a MOSFET or a bipolar transistor as the switch element. Experiments with MOSFETs presented me some difficulties charging the gate capacitance having some trouble to achieve something in the 4ns region. Well 4ns seems hard whatever device anyway. I would be happy to receive some comments/ideas that may pop out of your heads. Thanks. hope that my quest for fast rise "time" is not too off topic on this "time" list... but... there are so many experts on this list that I could not resist ;-) Luis Cupido ct1dmk. p.s. ( I switch a capacitor to GND with a transistor (fet or bipolar). that capacitor has a charging resistor to 48V, transformer has a 9:1 voltage ratio. Pulse average power is quite low a few watt only. At the primary side some 20A of peak current for less than 100ns... and very low duty cycle. ) _______________________________________________ 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. _______________________________________________ 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.