# Next: The tunnel diode oscillator.

Started by July 20, 2013
```Next: The tunnel diode oscillator.

Given an LC wit some Q (read damping),
if we can neutralize that R, would it start swinging all by itself?

Well how do you neutralize a resistor?
Simple:
put a negative resistor in series or parallel with it.

Mr Esaki invented the tunnel diode many years ago,
it has, at some point, a negative slope in its  I versus U curve.
So use a properly biased Esaki diode (also called tunnel ) diode connected
in some way to your LC, and it starts swinging,
actually the tunnel diode becomes an amplifier.
http://en.wikipedia.org/wiki/Tunnel_diode

Any takers? Anybody still have one?
```
```On Sat, 20 Jul 2013 19:59:10 +0000, Jan Panteltje wrote:

> Next: The tunnel diode oscillator.
>
> Given an LC wit some Q (read damping), if we can neutralize that R, would
> it start swinging all by itself?
>
> Well how do you neutralize a resistor? Simple:
>  put a negative resistor in series or parallel with it.
>
> Mr Esaki invented the tunnel diode many years ago, it has, at some point,
> a negative slope in its  I versus U curve. So use a properly biased Esaki
> diode (also called tunnel ) diode connected in some way to your LC, and it
> starts swinging, actually the tunnel diode becomes an amplifier.
>  http://en.wikipedia.org/wiki/Tunnel_diode
>
>
> Any takers? Anybody still have one?

I have loads. You can't have any...

--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
```
```On a sunny day (Sat, 20 Jul 2013 13:02:55 -0700) it happened Fred Abse
<excretatauris@invalid.invalid> wrote in
<pan.2013.07.20.20.02.53.232653@invalid.invalid>:

>On Sat, 20 Jul 2013 19:59:10 +0000, Jan Panteltje wrote:
>
>> Next: The tunnel diode oscillator.
>>
>> Given an LC wit some Q (read damping), if we can neutralize that R, would
>> it start swinging all by itself?
>>
>> Well how do you neutralize a resistor? Simple:
>>  put a negative resistor in series or parallel with it.
>>
>> Mr Esaki invented the tunnel diode many years ago, it has, at some point,
>> a negative slope in its  I versus U curve. So use a properly biased Esaki
>> diode (also called tunnel ) diode connected in some way to your LC, and it
>> starts swinging, actually the tunnel diode becomes an amplifier.
>>  http://en.wikipedia.org/wiki/Tunnel_diode
>>
>>
>> Any takers? Anybody still have one?
>
>I have loads. You can't have any...

Oh yes I can:
ebay.com
151 results for tunnel diode

Bye!
```
```On 7/20/2013 3:59 PM, Jan Panteltje wrote:
> Next: The tunnel diode oscillator.
>
> Given an LC wit some Q (read damping),
> if we can neutralize that R, would it start swinging all by itself?
>
> Well how do you neutralize a resistor?
> Simple:
>   put a negative resistor in series or parallel with it.
>
> Mr Esaki invented the tunnel diode many years ago,
> it has, at some point, a negative slope in its  I versus U curve.
> So use a properly biased Esaki diode (also called tunnel ) diode connected
> in some way to your LC, and it starts swinging,
> actually the tunnel diode becomes an amplifier.
>   http://en.wikipedia.org/wiki/Tunnel_diode
>
>
> Any takers? Anybody still have one?
>

I have about 50, iirc.  Not the really quick ones, which are up in the
100-200 mA I_p range--mine are about 5 mA.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510 USA
+1 845 480 2058

hobbs at electrooptical dot net
http://electrooptical.net
```
```On Sat, 20 Jul 2013 19:59:10 +0000, Jan Panteltje wrote:

> Next: The tunnel diode oscillator.
>
> Given an LC wit some Q (read damping),
> if we can neutralize that R, would it start swinging all by itself?
>
> Well how do you neutralize a resistor?
> Simple:
>  put a negative resistor in series or parallel with it.
>
> Mr Esaki invented the tunnel diode many years ago,
> it has, at some point, a negative slope in its  I versus U curve.
> So use a properly biased Esaki diode (also called tunnel ) diode
> connected in some way to your LC, and it starts swinging,
> actually the tunnel diode becomes an amplifier.
>  http://en.wikipedia.org/wiki/Tunnel_diode
>
>
> Any takers? Anybody still have one?

If they were the best way to make an oscillator then they'd still be made.

In general they're interesting toys, unless you happen to be keeping
equipment alive that uses them, or even are making equipment that just
won't work without them (which latter case I find hard to believe...)

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

```
```On Sat, 20 Jul 2013 19:59:10 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com>
wrote:

>Next: The tunnel diode oscillator.
>
>Given an LC wit some Q (read damping),
>if we can neutralize that R, would it start swinging all by itself?
>
>Well how do you neutralize a resistor?
>Simple:
> put a negative resistor in series or parallel with it.
>
>Mr Esaki invented the tunnel diode many years ago,
>it has, at some point, a negative slope in its  I versus U curve.
>So use a properly biased Esaki diode (also called tunnel ) diode connected
>in some way to your LC, and it starts swinging,
>actually the tunnel diode becomes an amplifier.
> http://en.wikipedia.org/wiki/Tunnel_diode
>
>
>Any takers? Anybody still have one?

I have lots of TDs. I was digging through dusty bins at Haltek, and they had one
box full. They didn't know what they were, so I bought a bunch for 10 cents
each.

Here are a couple of TD manuals:

https://dl.dropboxusercontent.com/u/53724080/Parts/Diodes/Ge1961TunnelDiodeManual.pdf

https://dl.dropboxusercontent.com/u/53724080/Parts/Diodes/Rca1963TunnelDiodeManual.pdf

They have all sorts of fun circuits.

I used to build a lot of TD circuits when I was a kid, mostly switching stuff.
My college senior project was "The Tunnel Diode Slideback Sampling Oscilloscope"

It's also fun to build a battery-powered 2-terminal negative resistor. Most
common electronic equations work when you plug in negative resistance values.

Hey, we could do a negative frictional resistor, too. Put that in parallel with
an LC and you'd get a linearly increasing envelope oscillation.

Haltek is gone, along with many other Silicon Valley surplus places.

http://www.bluefeathertech.com/technoid/surplusmemorial.html

That's what happens when you sell tunnel diodes for 10 cents.

--

John Larkin                  Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
```
```On a sunny day (Sat, 20 Jul 2013 15:22:00 -0500) it happened Tim Wescott
<tim@seemywebsite.really> wrote in
<e-6dnf8ga5P1bHfMnZ2dnUVZ5gGdnZ2d@giganews.com>:

>On Sat, 20 Jul 2013 19:59:10 +0000, Jan Panteltje wrote:
>
>> Next: The tunnel diode oscillator.
>>
>> Given an LC wit some Q (read damping),
>> if we can neutralize that R, would it start swinging all by itself?
>>
>> Well how do you neutralize a resistor?
>> Simple:
>>  put a negative resistor in series or parallel with it.
>>
>> Mr Esaki invented the tunnel diode many years ago,
>> it has, at some point, a negative slope in its  I versus U curve.
>> So use a properly biased Esaki diode (also called tunnel ) diode
>> connected in some way to your LC, and it starts swinging,
>> actually the tunnel diode becomes an amplifier.
>>  http://en.wikipedia.org/wiki/Tunnel_diode
>>
>>
>> Any takers? Anybody still have one?
>
>If they were the best way to make an oscillator then they'd still be made.

Yes, it was a practical problem,
they had only 2 pins, and fell over all the time,
while the 3 legged transistors stayed upright.

>In general they're interesting toys, unless you happen to be keeping
>equipment alive that uses them, or even are making equipment that just
>won't work without them (which latter case I find hard to believe...)
>
>--
>
>Tim Wescott
>Wescott Design Services
>http://www.wescottdesign.com
>
>
```
```On Sat, 20 Jul 2013 13:27:40 -0700, John Larkin wrote:

> On Sat, 20 Jul 2013 19:59:10 GMT, Jan Panteltje
> <pNaonStpealmtje@yahoo.com>
> wrote:
>
>>Next: The tunnel diode oscillator.

<< snip >>

> Haltek is gone, along with many other Silicon Valley surplus places.
>
> http://www.bluefeathertech.com/technoid/surplusmemorial.html

That's what happens when you provide the world with a convenient way to
catalog-shop from surplus vendors all over.  Because surplus vendors,
more than a lot of other places, depend on serendipitous matches of stock
with customer, being able to shop your stock to the widest variety of
people is what's going to make the business work -- that used to mean
being a surplus vendor in a physical spot with a lot of traffic of
interested people.  Now it means being good about having a good flexible
online cataloging system, and a smart stock-jock who knows what he's
selling.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

```
```Tim Wescott wrote:
> On Sat, 20 Jul 2013 13:27:40 -0700, John Larkin wrote:
>
>> On Sat, 20 Jul 2013 19:59:10 GMT, Jan Panteltje
>> <pNaonStpealmtje@yahoo.com>
>> wrote:
>>
>>> Next: The tunnel diode oscillator.
>
> << snip >>
>
>> Haltek is gone, along with many other Silicon Valley surplus places.
>>
>> http://www.bluefeathertech.com/technoid/surplusmemorial.html
>
> That's what happens when you provide the world with a convenient way to
> catalog-shop from surplus vendors all over.  Because surplus vendors,
> more than a lot of other places, depend on serendipitous matches of stock
> with customer, being able to shop your stock to the widest variety of
> people is what's going to make the business work -- that used to mean
> being a surplus vendor in a physical spot with a lot of traffic of
> interested people.  Now it means being good about having a good flexible
> online cataloging system, and a smart stock-jock who knows what he's
> selling.
>

There was another reason. I remember the Halted store here in town. From
behind the counter they sold components at reasonable prices. But most
of the store was full with old test equipment, floor to ceiling. And
there was the problem, this stuff was IMHO totally overpriced. Sometimes
easily 10x of what they charged at the next hamfest. So I never bought
any of that.

Having cheap Chinese scopes, generators, power supplies, meters and
whatnot did of course not help either.

--
Regards, Joerg

http://www.analogconsultants.com/
```
```>There was another reason. I remember the Halted store here in town. From
>behind the counter they sold components at reasonable prices. But most
>of the store was full with old test equipment, floor to ceiling. And
>there was the problem, this stuff was IMHO totally overpriced. Sometimes
>easily 10x of what they charged at the next hamfest. So I never bought
>any of that.

Well, a lot of it was/is overpriced compared to hamfests (hamfest
sales typically don't have anywhere near the overhead costs of store
sales).  Sometimes I've gotten lucky, though... got a 7S12 TDR/sampler
plugin with an S-2 sampler head and an S-52 pulser for about \$150,
which seems to work just fine.

```