Who remembers the tunnel diode? - Page 1
Forum section: electronics / general

author: GK
author_rank: Super Contributor
timestamp: October 02, 2012, 01:12:43 am
content: http://n4trb.com/AmateurRadio/SemiconductorHistory/GE_Tunnel_Diodes.pdfThe revolutionary new semiconductor device that, well, wasn’t.Does anyone know of a contemporary tunnel diode? Just curious and I wouldn’t mind experimenting with a few; but that might have to be with some ancient “NOS” acquired through Ebay.

author: FenderBender
author_rank: Super Contributor
timestamp: October 02, 2012, 01:15:54 am
content: Every time I walk into my shop I have to go through a series of spiritual rituals to make sure one of these doesn't die in my scope. Unobtanium!

author: GK
author_rank: Super Contributor
timestamp: October 02, 2012, 01:35:17 am
content: Ha! According to that GE article they are nuclear bomb proof! Is that a sampling oscilloscope?

author: GeoffS
author_rank: Unknown
timestamp: October 02, 2012, 02:06:35 am
content: I like the reference in the document to 'kilomegacycle'

author: RCMR
author_rank: Frequent Contributor
timestamp: October 02, 2012, 02:35:17 am
content: That's spooky -- I was just scanning the web for tunnel diodes the other day.I've got a 10GHz doppler radar module here that uses a tunnel diode and was wondering what to do if I blow it.Of course we've got better ways of creating microwave frequencies these days so for that application, the tunnel diode is redundant.

author: ee851
author_rank: Regular Contributor
timestamp: October 02, 2012, 03:02:58 am
content: I never heard of it. So I guess I wasn't an adult way back then. Whenever that was. There were things in glass vacuum tubes that were like diodes and amplifiers way back before my time. I never learned about them either. They're obsolete. But some hams still use them. I am a ham. So I would use one if I had one that stil worked.

author: Pentium100
author_rank: Frequent Contributor
timestamp: October 02, 2012, 03:28:45 am
content: The only time I saw a tunnel diode from up close was a few years ago in a lab - the assignment was to measure (and later plot) the IV curve. If I had one I would not know what to do with it - after all, it seems to me that it would be easier to build a transmitter with vacuum tubes than the tunnel diode (since IIRC all tunnel diodes are low power, so I would still have to use tubes to amplify the power). However, since I am incapable ow inding a coil (so it has specified parameters), I won't be building any transmitters any time soon.

author: RCMR
author_rank: Frequent Contributor
timestamp: October 02, 2012, 04:33:44 am
content: Back in the day, tunnel diodes were the easiest way to create a low-power microwave source.Many of the low-power X-band doppler radars (as used in home-security systems and as automatic door-openers back in the 1970s/80s) were tunnel diode based.Just throw a tunnel diode in a resonant cavity, bias it appropriately and bingo -- instant microwave-source.I think the unit I have is about 5-8mW at 10.5GHz.

author: Lukas
author_rank: Frequent Contributor
timestamp: October 02, 2012, 05:18:43 am
content: Quote from: RCMR on October 02, 2012, 04:33:44 amGunn diodes do the job as well and are much less unobtainium.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 02, 2012, 05:49:19 am
content: Tunnel diodes were used extensively at one time,but their performance was overtaken by more conventional devices.The only thing I remember using which used them was a TU-5 Pulser,which,when driven by the reasonably slow calibration signal,produced a fast rise time pulse allowing you to test an oscilloscope's transient response.

author: G7PSK
author_rank: Super Contributor
timestamp: October 02, 2012, 07:22:18 am
content: In the late 60's there was a record held by a radio amateur for long distance transmission with low power, from Newzealand to America with less than a quarter watt using a tunnel diode transmitter.

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 02, 2012, 09:38:15 am
content: I remember buying one as a teenager. It looked like a very interesting device to build a small transmitter.Unfortunately it was expensive (for me) and I never got it working, probably killed itThat was my first and last tunnel diode experiment. I wonder if it is still in one of the weird stuff drawers...

author: vis1-0n
author_rank: Contributor
timestamp: October 02, 2012, 11:18:24 am
content: Quote from: PA0PBZ on October 02, 2012, 09:38:15 amI was around 13-15 years old in the early 90's and I remember finding the schematics to FM transmitters in one of those 1001 "Electronics circuits"-type books at the public reference library. It had no exotic (GE,HF) transistors, just resistors and capacitors to go with the TD. It seemed so super simple that I walked around the shops looking for one in vain.

author: saturation
author_rank: Super Contributor
timestamp: October 02, 2012, 12:18:51 pm
content: I still use it on my venerable Tek 284 pulse generator reference. 70ps or less and 1 GHz reference signals made in the 1960s.There is still quite a bunch of overstock easily found on eBay. IIRC Russia still makes them new.http://www.ebay.com/sch/?_nkw=tunnel%20diodes&clk_rvr_id=393658061107

author: G7PSK
author_rank: Super Contributor
timestamp: October 02, 2012, 12:20:40 pm
content: Just came across this on the net after a Google search on tunnel diodes.http://www.sparkbangbuzz.com/els/ntype-nr-el.htm

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: October 02, 2012, 02:28:38 pm
content: I had one of these , it was in a small / cheap GDO - Grid Dip Oscillator , from Heathkit .I quickly moved on to several other GDOs that performed much better , but were much bigger .http://www.radiomuseum.org/r/heath_tunnel_dipper_hm_10_a_hm1.html

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 02, 2012, 02:35:32 pm
content: Quote from: KD0CAC John on October 02, 2012, 02:28:38 pmThat would make it a TDO then?

author: GK
author_rank: Super Contributor
timestamp: October 03, 2012, 06:27:11 am
content: Quote from: vk6zgo on October 02, 2012, 05:49:19 amYes, that is what I would like to do. Looks like I have plenty NOS to choose from on ebay.