EMRFD Message Archive 3200
Message Date From Subject 3200 2009-06-17 17:45:11 Paul Anderson Tunnel diodes?
---
Paul Anderson
wackyvorlon@gmail.com
http://www.andersonloco.com3201 2009-06-17 18:31:51 Art Re: Tunnel diodes?
There is one vendor who does periodic runs, I forget the name though.
But, they charge a very ridiculous price for them, I think it was
well over $10 each. You do get to choose the electrical
characteristics though, but I think it's a 2000 piece minimum order.
The Gunn devices are nearly identical and cost a bunch less and are available.
The is an equivalent circuit that can be made from jfets or mosfets
and some resistors....the output characteristics show the same
negative resistance however, so they can be used to study the
negative resistance phenomena.
They do show up on ebay, generally selling from $3 to $5 each, plus shipping.
I think wikipedia has a pretty good article on the tunnel diode.
Regards,
Art
>I was wondering if any companies still manufacture tunnel diodes.
>
>--3202 2009-06-18 00:13:24 Ian White GM3SEK Re: Tunnel diodes?
>Even at best, tunnel diodes were cranky devices, not well characterized
>>I was wondering if any companies still manufacture tunnel diodes.
>>
>There is one vendor who does periodic runs, I forget the name though.
>
>But, they charge a very ridiculous price for them, I think it was
>well over $10 each. You do get to choose the electrical
>characteristics though, but I think it's a 2000 piece minimum order.
>
>The Gunn devices are nearly identical and cost a bunch less and are
>available.
>
>The is an equivalent circuit that can be made from jfets or mosfets
>and some resistors....the output characteristics show the same
>negative resistance however, so they can be used to study the
>negative resistance phenomena.
>
>They do show up on ebay, generally selling from $3 to $5 each, plus
>shipping.
>
>I think wikipedia has a pretty good article on the tunnel diode.
>
and difficult to design with. As Art points out, there are more
predictable equivalent circuits for low frequency use, and today there
are also much better devices for amplifiers and oscillators at VHF+.
They say "Nostalgia ain't what it used to be"... and for tunnel diodes,
that may be literally true. The original devices are now 30-40 years
old, and there is some question whether the extremely high doping
gradients might have relaxed by diffusion over this long time period.
--
73 from Ian GM3SEK3203 2009-06-18 01:04:30 leon Heller Re: Tunnel diodes?
3204 2009-06-18 03:18:44 Johan H. Bodin Re: Tunnel diodes?
exhibits negative resistance.
http://users.tpg.com.au/users/ldbutler/NegativeResistance.htm
http://users.tpg.com.au/users/ldbutler/NegResDipMeter.htm
http://en.wikipedia.org/wiki/Lambda_diode
http://www.inictel.gob.pe/pdf/investigacion/oscillations%20and%20regenerative%20amplification%20using%20negative%20resistance%20devices.pdf
73
Johan SM6LKM
Art wrote:
>
> The is an equivalent circuit that can be made from jfets or mosfets
> and some resistors....the output characteristics show the same
> negative resistance however, so they can be used to study the
> negative resistance phenomena.3205 2009-06-18 06:01:06 Chris Trask Re: Tunnel diodes?
>I was wondering if any companies still manufacture tunnel diodes.
>
Tunnel diodes are interesting devices. There is a fellow out there who has a design for a QRP transceiver using one.
Chris
,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_3206 2009-06-18 08:47:38 Art Re: Tunnel diodes?
'avalanche' transistor (bipolar) that exhibits negative resistance
with built in gain. The gain is somewhat lower than other
conventional transistors though. I do not know whether they have
complementary pairs or whether they can be made in both N and P types.
There is a QRP'er who has a mictorwatt beacon that he puts on 80
meters and I think he's set the current record for miles per watt at
4,000,000 miles per watt.
He also developed a qrp transceiver using nothing but tunnel diodes.
Enjoy.
Art
>Yes, the "lambda circuit" can be built from two J-FETs, N+P, and it
>exhibits negative resistance.
>
>
>http://users.tpg.com.au/users/ldbutler/NegativeResistance.htm
>http://users.tpg.com.au/users/ldbutler/NegResDipMeter.htm
>http://en.wikipedia.org/wiki/Lambda_diode
>http://www.inictel.gob.pe/pdf/investigacion/oscillations%20and%20regenerative%20amplification%20using%20negative%20resistance%20devices.pdf
>
>
>73
>Johan SM6LKM
>
>
>Art wrote:
> >
> > The is an equivalent circuit that can be made from jfets or mosfets
> > and some resistors....the output characteristics show the same
> > negative resistance however, so they can be used to study the
> > negative resistance phenomena.
>
>
>
>------------------------------------
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>06/16/09 21:23:003207 2009-06-18 08:59:23 leon Heller Re: Tunnel diodes?
3208 2009-06-18 10:16:32 Paul Anderson Re: Tunnel diodes?
>EEK. So... gunn diodes you say have similar characteristics? Anybody
> Here is someone who supplies them:
>
> http://store.americanmicrosemiconductor.com/diodes-tunnel-diodes.html
>
> They aren't cheap!
>
played with gunn diodes?
---
Paul Anderson
wackyvorlon@gmail.com
http://www.andersonloco.com3209 2009-06-18 10:48:26 Dave Re: Tunnel diodes? 3210 2009-06-18 10:57:09 Dave Re: Tunnel diodes? 3211 2009-06-18 10:57:18 leon Heller Re: Tunnel diodes?
3212 2009-06-18 11:01:45 Dave Re: Tunnel diodes? 3213 2009-06-18 11:14:22 leon Heller Re: Tunnel diodes?
experimental tunnel diode memory array in the lab.
Leon3214 2009-06-18 11:15:27 leon Heller Re: Tunnel diodes?
3215 2009-06-18 11:47:25 Wes Hayward Re: Tunnel diodes?
The short question about tunnel diodes certainly created a flood of responses, all of them interesting. I have a friend (Bob, N7FKI) who has always been interested in the more obscure semiconductor devices and especially the tunnel diode. He has built transmitters and receivers with them on all sorts of bands. I copied the TD response from Art (Ky1K) and sent it to him. I thought that the group would be interested in Bob's comment.
73, Wes
-----------------------------------------
Hi Wes,
That's a pretty good description. I'm not sure that Gunn diodes are very much like tunnel diodes, however, since they are avalanche devices. Tunnel diodes are heavily doped pn junctions to promote the excess (tunneling) current at low voltage. It is when the applied voltage increases the depletion layer that the tunneling current subsides forming the negative resistance region.
We now know that the tunnel diode was first invented and described by Robert Noyce when he was at Shockley Labs. Shockley killed his project because he saw no use for the device. Noyce's notebooks show a perfect description of the device with characteristic curves and proper theory. Leo Esaki stumbled into the device when excess currents were observed while trying to figure out the poor yields of Sony germanium transistors. A lab technician actually noted the effect but Esaki figured out what was causing it. His one-page paper
earned him a Nobel Prize (shared three ways, actually). Esaki went on to develop resonant tunneling structures at IBM.
Tunnel diodes were most used by Tektronix in oscilloscope triggering circuits. Tek eventually figured out how to eliminate them with high speed ECL circuits. They survived as LNAs in satellites because (due to the high doping) space radiation couldn't kill them.
There are tunnel diodes on ebay from time to time. Aeroflex/Metelics sells them as well, mainly as low level detectors.
There are very low current devices called back diodes such as the BD-4 that Tek stocked. It had a peak current of 0.1 mA and a very high negative resistance.
I first paid $9.50 each for my first two tunnel diodes (1N2939), which were 1 mA peak devices. I promptly burned out the first one by not limiting the input current from a 1.5 volt battery. That was an expensive lesson. The second one still works.
GE was the largest manufacturer of tunnel diodes and produced the well-known data book with applications for the devices. RCA also made devices in strip line form that Tek also used. RCA made some devices with peak currents of up to 100 amps. These would make interesting transmitter devices since one could probably get a
watt output with them. One can fake a high current TD by connecting a low current TD between the collector and base of a bipolar power transistor, which is then used as a two terminal device. Since everything works by quantum mechanics, this seems fair.
73, Bob
--------------------------3216 2009-06-18 11:58:43 k5nwa Re: Tunnel diodes? 3217 2009-06-18 12:47:01 Art Re: *****SPAM***** Re: [emrfd] Re: Tunnel diodes?
>3220 2009-06-19 12:04:38 Dave Re: Tunnel diodes? 3222 2009-06-19 13:28:51 Glen Leinweber Re: Tunnel diodes?
mine don't drift away into the trash!
Seems to me that Gunn diodes depend on transit-time
between junctions, and therefore won't work at HF the way
tunnel diodes will. Gunn oscillators are UHF and up, and are
usually accompanied with a resonator that better-defines the
oscillating frequency. A tunnel diode can be tested on a 60Hz.
curve tracer (except for the negative-resistance region, which
drives the curve-tracer nuts). Do I recall that someone
once found that some rectifier diodes (like 1N4007) had
Gunn-like abilities, or do I have negative-resistance-on-the-
brain?
Another negative resistance device is a neon bulb, and a
few old folks (me included) have built RC relaxation
oscillators with these. Are bayonet neon bulbs still available?
Since slow ions are involved, I'll bet there's an upper frequency
limit here - can't recall seeing a HF neon oscillator.
In some sense, negative resistance is VERY common - you
can regard snap diodes, flip-flops, Schmidtt triggers, SCRs &
triacs as negative resistance devices, if you twist your brain
just right ;-)3223 2009-06-19 15:25:08 leon Heller Re: Tunnel diodes?
> once found that some rectifier diodes (like 1N4007) hadThe 1N4007 has a PIN diode construction, and has been used as an RF switch
> Gunn-like abilities, or do I have negative-resistance-on-the-
> brain?
or attenuator.
Leon3225 2009-06-20 03:38:22 Paul Anderson Re: Tunnel diodes?
>Isn't that a Wien bridge oscillator?
> Another negative resistance device is a neon bulb, and a
> few old folks (me included) have built RC relaxation
> oscillators with these.
---
Paul Anderson
wackyvorlon@gmail.com
http://www.andersonloco.com3226 2009-06-20 03:47:18 leon Heller Re: Tunnel diodes?