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Re: Frequency range of HP 5352B frequency counter
wrote: The unit I bought arrived at my friends, but the higher frequency input was non-functional. Luckily the seller had another, which functioned okay. But there seems to be a hard limit at 43 GHz.
By Dr. David Kirkby, Kirkby Microwave Ltd · #126626 ·
Re: HP 3465A offset when input shorted
Got it. That's confirmed here as well. Doing too many tasks at the same time here to do any of them properly. I shall sit in the corner for a few mins with the dunce hat on! By elimination of ideas,
By Chris Smith <me@...> · #126625 ·
Re: HP 3465A offset when input shorted
Agreed. The anode of CR9 is held at approximately -3.92 V unless something takes current away from CR11 and the only thing that can do that is reverse current through CR9. Orin.
By Orin Eman · #126624 ·
Re: HP 3465A offset when input shorted
---- When the node is clamped to let's say +5V, CR9 has (+5V-(-3.92V))=8.92V reverse bias. In the sim you should see CR8 and CR9 seeing ~ 2*3.92V+0.7V reverse bias in the extremes of the over voltage
By Ozan · #126623 ·
HP 3465A offset when input shorted
Chris Smith: Looking at the schematic there is indeed polarity clamps for + & - excursions using CR9 & CR 8 going to 3.9V zenerdiodes, CR11 & CR10, that reverse bias the actual clamping diodes CR 8 &
By Goran Finnberg · #126622 ·
Re: HP 8662A Power up - overvoltage shutdown
Agreed. That would be extremely useful. The -40V rail's operating spec max is 0.5A - so I can increase the current dummy load I have in place by quite a way yet - I'll try that next. thanks Tony
By Tony · #126621 ·
Re: HP 3465A offset when input shorted
I did a simulation of the clamp and it clamps at 5v, both polarities which is under the 6v reverse breakdown so the thing shouldn't get zenered. It's a bit tight though! As for the JFET pricing, it's
By Chris Smith <me@...> · #126620 ·
Re: HP 3465A offset when input shorted
FWIW, Mouser have over 8000 PN4117A. at $3.17 each. I don't know how easy/expensive to get them to ship in the UK though. You don't need the metal can version - HP switched to plastic packages for
By Orin Eman · #126619 ·
Re: HP 3465A offset when input shorted
Orin Eman: The B-E diode is zenered by back reversing it. It increases 100s times or more increases the B-E diode leakage if zenered once. There is a need for back to back 2N3904 B-E diodes to avoid
By Goran Finnberg · #126618 ·
Re: HP 3465A offset when input shorted
The 1901-0586 is also used in the 34702A, in which it is listed as "DIODE: SI 30 WV 10PA LEAKAGE", so I would say that a low-leakage JFET would be a perfect choice as a replacement. A 2N4117 or its
By Joel Setton · #126617 ·
Re: HP 3465A offset when input shorted
Yes, a 2N3904 B-E is next best after the FETs for leakage, but doesn't have a very good reverse breakdown spec - only 6V.
By Orin Eman · #126616 ·
Inert Gas
Has anyone used canned air (R134a, er=1.0113, plus a bittering agent) to backfill sealed HP modules? I don't have any dry nitrogen on hand, canned air doesn't seem to kill the performance, and it
By jjoonathan · #126615 ·
Re: Frequency range of HP 5352B frequency counter
As to my knowledge option 005 was never covered by the regular service manual , back in my tucker days I remember seeing a addendum that was published to be added to the service guide that covered the
By Lothar baier <Lothar@...> · #126614 ·
Re: HP 3465A offset when input shorted
There is separate protection for the AC, ohms and current ranges from what I can see. I haven't traced the whole thing out here or checked the whole DMM out yet, only the DC path.
By Chris Smith <me@...> · #126613 ·
HP 3465A offset when input shorted
Chris Smith: Good to know. I will look at the schematic later this evening to see what they have done. Strange to clamp later on leaving the input buffer amp and AC converter open to burn out. But
By Goran Finnberg · #126612 ·
Re: HP 3465A offset when input shorted
Low capacitance is not an issue as it's after the AC converter so low voltage slew. It can be considered a DC amplifier with very low bandwidth at that point. There is actually 0.1uF to ground anyway
By Chris Smith <me@...> · #126611 ·
HP 3465A offset when input shorted
Chris Smith: What about capacitive loading at the clamp point ? Looking at the service manual for 5 minutes I see no spec for the accuracy when fed 100 kHz compared to 50/60 Hz. I am thinking that it
By Goran Finnberg · #126610 ·
HP/Agilent/Keysight VEE for a reasonable price?
Hi all, I'm looking to get my hands on a copy of the HP/Keysight VEE Pro software development package for tinkering around, but I'm not able to fork out the full cost of the current version for my
By Jared Cabot · #126609 ·
Re: Frequency range of HP 5352B frequency counter
Dave , Incorrect, the 46GHz used a 2.4mm , it was a connector that is similar to the ones used on VNA (NMD type) , google pictures of the 52B with option 05 and you see the difference
By Lothar baier <Lothar@...> · #126608 ·
Re: HP 3465A offset when input shorted
Thanks all for the replies. I looked into this as well and came across similar FETs. The only problem is obtaining them cost more than I paid for the meter. It turns out the B-E junction of a 2n3904
By Chris Smith <me@...> · #126607 ·
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