Author Topic: New version Pulse Generator (based Jim Williams Pulse Gen) (Read 30871 times)

free_electron · « **Reply #25 on:** October 27, 2015, 07:32:25 pm »

you can make that pulse go faster by doing dead spider. right now you have a parasite with the ground plane being so close to output and coax

http://www.siliconvalleygarage.com/eevblog/cal/Calibration%20Certificate%204.pdf

155ps easy.

BFX · « **Reply #26 on:** March 20, 2017, 05:55:51 pm »

After around two years of using this PG a have only few suggestion's.
- I was surprised using BNC connector and I think SMA would be better. (but it's work relatively fine)
- and as said my friend different is only at PCB design and this longer OnTime which I'm not sure if it's improvement. (little bit design change would be big improvement)
- max-bit it's really bad if you move or remove images which is used in this thread (please upload it to eevblog or repair your links)

tecman · « **Reply #27 on:** March 20, 2017, 08:33:10 pm »

Does anybody have a PCB or kit to sell yet ?

Paul

rodd · « **Reply #28 on:** March 21, 2017, 03:29:06 pm »

Quote from: tecman on March 20, 2017, 08:33:10 pm

Does anybody have a PCB or kit to sell yet ?

Paul

If affirmative, I am also interested.
Thanks.

Enviado do meu iPhone usando Tapatalk

free_electron · « **Reply #29 on:** March 21, 2017, 03:30:24 pm »

i just got a batch of boards in for my pulse generator design ( about 100 pieces ).

5$ + shipping for a pcb. ( in the us that is a regular envelope with stamp)

i need to see if i can scavenge some more of the gold plated transistors. will post an update over the weekend.

all_repair · « **Reply #30 on:** March 21, 2017, 04:33:16 pm »

Mark me for 2 sets, with or without parts, out of US. If mailing out of US a hassle, I have a forwarding address in US also. THANKS.

macboy · « **Reply #31 on:** March 21, 2017, 04:38:29 pm »

Quote from: free_electron on March 21, 2017, 03:30:24 pm

i just got a batch of boards in for my pulse generator design ( about 100 pieces ).

5$ + shipping for a pcb. ( in the us that is a regular envelope with stamp)

i need to see if i can scavenge some more of the gold plated transistors. will post an update over the weekend.

Does your design use a capacitor or a transmission line (coax or stripline) for charge storage?
In other words, does the generated pulse have an upper plateau (i.e. a step), or is it just a hump (i.e. an impulse)?

metrologist · « **Reply #32 on:** March 21, 2017, 04:48:53 pm »

Quote from: macboy on March 21, 2017, 04:38:29 pm

Quote from: free_electron on March 21, 2017, 03:30:24 pm
i just got a batch of boards in for my pulse generator design ( about 100 pieces ).

5$ + shipping for a pcb. ( in the us that is a regular envelope with stamp)

i need to see if i can scavenge some more of the gold plated transistors. will post an update over the weekend.
Does your design use a capacitor or a transmission line (coax or stripline) for charge storage?
In other words, does the generated pulse have an upper plateau (i.e. a step), or is it just a hump (i.e. an impulse)?

Me two, I'm interested in the details. Is there a circuit?

free_electron · « **Reply #33 on:** March 21, 2017, 04:56:58 pm »

yes, my design has a strip line and has a plateau.

about 80 of these have been built and they have been measured on one of the most performant oscilloscopes in the world :
DSA-X 93204A: 32GHz analog bandwidth. 80 Gigasamples per second on 4 channels ,2.1 Billion points of memory, PER channel.

project :

http://siliconvalleygarage.com/projects/picosecond-pulser.html

macboy · « **Reply #34 on:** March 21, 2017, 05:14:08 pm »

Quote from: free_electron on March 21, 2017, 04:56:58 pm

yes, my design has a strip line and has a plateau.

about 80 of these have been built and they have been measured on one of the most performant oscilloscopes in the world :
DSA-X 93204A: 32GHz analog bandwidth. 80 Gigasamples per second on 4 channels ,2.1 Billion points of memory, PER channel.

...

project :

http://siliconvalleygarage.com/projects/picosecond-pulser.html

Very nice. Just long enough pulse for risetime measurements, not so long as to stress/kill the Q1 prematurely.
I see you use the good old 2N2369. I have a few of these NOS, original Motorola, made decades ago (still in factory packaging). I've been keeping them for this type of project. Now that I have a 2 GHz scope, I'm motivated. Definitely mark me down for two PCBs. I'd also be interested in full or partial kits. Letter mail to Canada shouldn't be an issue, I've received quite a few different non-document things via letter mail from the USA.

H.O · « **Reply #35 on:** March 21, 2017, 05:25:42 pm »

Yes I'm (still) interested in a PCB (with or witout any parts) if you can ship to Europe (at my cost of course).

steverino · « **Reply #36 on:** March 21, 2017, 06:33:32 pm »

free_electron, please count me in for a pcb.

Gixy · « **Reply #37 on:** March 21, 2017, 06:40:31 pm »

Hi Vincent,
Welcome back with your splendid pulse generator. One PCB for me too, preferably with the gold plated transistor

.
Thx,
Denis

HighVoltage · « **Reply #38 on:** March 21, 2017, 06:47:51 pm »

I would like to take one of your PCB's as well.
Thanks

free_electron · « **Reply #39 on:** March 21, 2017, 06:48:31 pm »

right . let me dig in my garage to see if i still have a pile of those transistors ( i think i do ) gold plated legs. NOS SGS or Motorola's.
i will create a separate topic where you can place the request. I need ot check for shipping internationally what they charge these days. i would do board + transistor. the rest you need to take care of yourself ( i did complete kits previously but that takes a lot of time. if there is enough demand we could do that again. all parts are available at digikey.

let me organise my thoughts and i will set it up.

tecman · « **Reply #40 on:** March 21, 2017, 07:14:14 pm »

I am interested in one as well, and a kit with parts would be great.

paul

kaz911 · « **Reply #41 on:** March 21, 2017, 08:58:01 pm »

And me too please

with transistor if at all possible (US/Fl shipping address)

JPortici · « **Reply #42 on:** March 21, 2017, 09:38:25 pm »

So there still are pcbs. One or two for me too! advice on parts?
(There *shouldn't* be anything that esoteric, right?)

SvanGool · « **Reply #43 on:** March 21, 2017, 09:39:46 pm »

I would like one of your PCBs too

james_s · « **Reply #44 on:** March 21, 2017, 10:18:24 pm »

I've gotten interested in building a pulse generator for some TDR experiments. There's a nice looking TDR adapter design on Mr. Carlson's lab but he didn't go into much detail on component choices. I know the transistor needs to be carefully selected but how critical is the capacitor? Can I expect reasonable performance using any old ceramic chip cap I find in the right value or does it need to be something specific? Extremely fast risetime pulses are new territory for me.

Rycroft · « **Reply #45 on:** March 21, 2017, 10:50:35 pm »

I'll take a PCB and transistor if you will ship to Australia.

amspire · « **Reply #46 on:** March 21, 2017, 11:32:45 pm »

I will take one. Looks like TO18 packaged 2N2369's are available in Australia at a good price - don't know if it is the gold plated leg one, but I will get some and see.

eliocor · « **Reply #47 on:** March 21, 2017, 11:41:34 pm »

I would be interested in 2 pieces...

djnz · « **Reply #48 on:** March 22, 2017, 02:58:43 am »

I'd be interested as well. Thank you for doing this.

amspire · « **Reply #49 on:** March 22, 2017, 03:33:48 am »

If anyone in Australia is interested, particularly if they are in Melbourne, Rockby have 13 x 2N2369 transistors in stock for under $1.40 each. If you have to use mail order, that is an extra $10.

https://www.rockby.com.au/SearchresSql_12.cfm?Searchkey=2n2369

I haven't been following the pulse generator discussion well enough to know if there are good and bad versions of this transistor.


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Author Topic: New version Pulse Generator (based Jim Williams Pulse Gen) (Read 30871 times)

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