Low voltage negative resistance oscillator design, lessons l

[piglet]

On 09/08/2019 21:28, Piotr Wyderski wrote:

bitrex wrote:

I don't think I've ever even _seen_ a tunnel diode in the real world,
much less used one for anything! aren't they usually used for
microwave frequency oscillators and such? I'm not going that fast.

Give them a bulky tank circuit and they will go as low as 1MHz.
But what are you tryig to achieve?

    Best regards, Piotr

There isn't a lower limit, tunnel diodes can do audio too.

piglet

 

[Piotr Wyderski]

Jan Panteltje wrote:

> Yes, JFET oscilators work from almost zero volts upward, done that:

It should be possible to make a combo: the JFET one as a gate supply
circuit for a very low R_DS_ON MOSFET for high-power applications.
Thermocouples can produce helluva amps, wasting them is a pity.
The JFET is switching voltage, the MOSFET is switching current, so to
speak...

Best regards, Piotr

 

[Jan Panteltje]

On a sunny day (Fri, 9 Aug 2019 22:49:10 +0200) it happened Piotr Wyderski
<peter.pan@neverland.mil> wrote in <qikm84$5gn$1@gioia.aioe.org>:

Jan Panteltje wrote:

Yes, JFET oscilators work from almost zero volts upward, done that:

It should be possible to make a combo: the JFET one as a gate supply
circuit for a very low R_DS_ON MOSFET for high-power applications.
Thermocouples can produce helluva amps, wasting them is a pity.
The JFET is switching voltage, the MOSFET is switching current, so to
speak...

Best regards, Piotr

Yes, done that too:
http://panteltje.com/pub/lighting_a_LED_with_a_candle_circuit_diagram_with_added_power_MOSFET.gif

The gate voltage at the JFET is enough to switch an IRLZ34N on / off.

Now all you need is some hot plutonium... for an RTG.

Magnifying lens, sun?
Efficiency better than a solar panel?

Gotto try

 

[Clifford Heath]

On 9/8/19 2:52 am, bitrex wrote:

On 8/8/19 4:29 AM, Jan Panteltje wrote:
On a sunny day (Thu, 8 Aug 2019 03:24:11 -0400) it happened bitrex
user@example.net> wrote in <w6Q2F.342353$5i.35921@fx46.iad>:

Don't bother with discretes if you want a negative resistor when you
have low psu headroom, all the discrete negative resistance topologies,
lambda diodes, foldback limiters, etc. are bad at a couple volts and are
seriously fussy with respect to how you load them and have lousy tempcos
down there.

get an AD8515 for 45 cents and save yourself the trouble

You did not try a tunnel diode?


I don't think I've ever even _seen_ a tunnel diode in the real world,
much less used one for anything! aren't they usually used for microwave
frequency oscillators and such? I'm not going that fast.

The Apollo Unified S-band communications (USB) used parametric
amplifiers on receive, I think using TDs rather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

Clifford Heath.

 

[whit3rd]

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:

On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

<https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97>

The AD310 usually sat in a teflon-bushed socket and might have to be hand-wired,
but it gave the vacuum-tube vibrating reed electrometers some real solid state
competition on leakage current. After all, if you bias a varactor at zero volts,
what IS the expected DC current?

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1
979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

Offset voltages could wreak havoc:

1 mV / 1 pV = 1 GOhm

 

[piglet]

On 31/08/2019 12:39 am, Clifford Heath wrote:

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

Clifford Heath.

This drawing shows one way:

<https://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Cavity_Parametric_Amplifier.gif>

Here are several quirky things all going together:

<http://www.qrp.gr/technology/diodes_only/mjrainey/tunneldiodereceiver.html>

piglet

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Saturday, August 31, 2019 at 1:59:38 AM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier.

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

Offset voltages could wreak havoc:

1 mV / 1 pV = 1 GOhm

But the inverting node was the sensitive one; the noninverting node was
usually grounded with a nice low impedance wire. That left the
inverting node for making a transimpedance amplifier, converting current
to voltage... with an unamplified DC offset added at the output
terminal. No havoc in that configuration.

Where did you find that information? I tried to find a datasheet without
success. If you have one, can you post it?

 

[whit3rd]

On Saturday, August 31, 2019 at 1:59:38 AM UTC-7, Steve Wilson wrote:

whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier.

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

Offset voltages could wreak havoc:

1 mV / 1 pV = 1 GOhm

But the inverting node was the sensitive one; the noninverting node was usually
grounded with a nice low impedance wire. That left the inverting node for making
a transimpedance amplifier, converting current to voltage... with an unamplified DC offset
added at the output terminal. No havoc in that configuration.

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Sunday, September 1, 2019 at 12:08:07 AM UTC-7, Steve Wilson wrote:

Where did you find that information? I tried to find a datasheet
without success. If you have one, can you post it?

The old data catalog here
https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1
979/page/n97> has the info, pages 97ff. I think they called it the
'310' with no letters prefixed, and that'd be a hard string to search
on.

Thanks. I didn't know you could page through by left-clicking.

 

[whit3rd]

On Sunday, September 1, 2019 at 12:08:07 AM UTC-7, Steve Wilson wrote:

whit3rd <whit3rd@gmail.com> wrote:

On Saturday, August 31, 2019 at 1:59:38 AM UTC-7, Steve Wilson wrote:

The AD310 usually sat in a teflon-bushed socket...

Offset voltages could wreak havoc:

1 mV / 1 pV = 1 GOhm

But the inverting node was the sensitive one; the noninverting node was
usually grounded with a nice low impedance wire. That left the
inverting node for making a transimpedance amplifier, converting current
to voltage... with an unamplified DC offset added at the output
terminal. No havoc in that configuration.

Where did you find that information? I tried to find a datasheet without
success. If you have one, can you post it?

The old data catalog here <https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97>
has the info, pages 97ff. I think they called it the '310' with no letters prefixed,
and that'd be a hard string to search on.

 

[Clifford Heath]

On 31/8/19 4:37 pm, whit3rd wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to be hand-wired,
but it gave the vacuum-tube vibrating reed electrometers some real solid state
competition on leakage current. After all, if you bias a varactor at zero volts,
what IS the expected DC current?

That uses a pump signal at well above the signal frequency. It's pretty
hard to see how you could build an s-band amplifier that way.

 

[piglet]

On 01/09/2019 23:25, Clifford Heath wrote:

On 31/8/19 4:37 pm, whit3rd wrote:
On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97


The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired,
but it gave the vacuum-tube vibrating reed electrometers some real
solid state
competition on leakage current.   After all, if you bias a varactor at
zero volts,
what IS the expected DC current?


That uses a pump signal at well above the signal frequency. It's pretty
hard to see how you could build an s-band amplifier that way.

AFAIK they did, using X, Ku, or K band pumps. Then downconverting using
conventional noisy devices.

To get gain in a para-amp requires the pump frequency to be higher than
the input signal?

piglet

 

[Phil Hobbs]

On 9/1/19 6:25 PM, Clifford Heath wrote:

On 31/8/19 4:37 pm, whit3rd wrote:
On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath
wrote:
On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier.
Does anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97



The AD310 usually sat in a teflon-bushed socket and might have to
be hand-wired, but it gave the vacuum-tube vibrating reed
electrometers some real solid state competition on leakage current.
After all, if you bias a varactor at zero volts, what IS the
expected DC current?


That uses a pump signal at well above the signal frequency. It's
pretty hard to see how you could build an s-band amplifier that way.

When I was an undergrad, circa 1980-81, I had a research assistantship
with Professor Bill Shuter (radio astronomer and all-round good guy).
He had a millimeter-wave radio telescope that looked for carbon-12 and
carbon-13 monoxide emission at 115 and 110 GHz, respectively, for
probing the structure of interstellar giant molecular clouds.

The front end was a cooled parametric downconverter, followed by an
X-band GaAs FET IF amp, another downconverter, and a filter bank. (FFTs
were still too slow in those days.)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1
979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

I am trying to understand how this worked. There is a diagram of the input
circuit on page 3 of the file. Do you have any idea of the frequency and
amplitude of the signal fed to the bridge?

 

On Monday, September 2, 2019 at 10:25:21 PM UTC+2, j.p...@student.utwente.nl wrote:

On Monday, September 2, 2019 at 8:33:48 PM UTC+2, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1
979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

I am trying to understand how this worked. There is a diagram of the input
circuit on page 3 of the file. Do you have any idea of the frequency and
amplitude of the signal fed to the bridge?

I did a teardown of one and reverse-engineered it:
https://imgur.com/jRxgMy4

Haven't bothered to figure out the color coding on the resistors. The feedback to the "front-end" (post-bridge) JFET still somewhat mystifies me.

I'll hang my scope on it tomorrow to check the frequency. I seem recall the Philbrick P2 operating around 5MHz.

Seems I screwed up the imgur post.
Anyhow, here's the whole thing: https://imgur.com/a/EPRpTgq

 

On Monday, September 2, 2019 at 8:33:48 PM UTC+2, Steve Wilson wrote:

whit3rd <whit3rd@gmail.com> wrote:

On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath wrote:
On 9/8/19 2:52 am, bitrex wrote: ather than varactors.

It's a curious thought though, using a varactor as an amplifier. Does
anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1
979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to be
hand-wired, but it gave the vacuum-tube vibrating reed electrometers
some real solid state competition on leakage current. After all, if
you bias a varactor at zero volts, what IS the expected DC current?

I am trying to understand how this worked. There is a diagram of the input
circuit on page 3 of the file. Do you have any idea of the frequency and
amplitude of the signal fed to the bridge?

I did a teardown of one and reverse-engineered it:
https://imgur.com/jRxgMy4

Haven't bothered to figure out the color coding on the resistors. The feedback to the "front-end" (post-bridge) JFET still somewhat mystifies me.

I'll hang my scope on it tomorrow to check the frequency. I seem recall the Philbrick P2 operating around 5MHz.

 

[Steve Wilson]

j.ponte@student.utwente.nl wrote:

I did a teardown of one and reverse-engineered it:
https://imgur.com/jRxgMy4

Haven't bothered to figure out the color coding on the resistors. The
feedback to the "front-end" (post-bridge) JFET still somewhat mystifies
me.

I'll hang my scope on it tomorrow to check the frequency. I seem recall
the Philbrick P2 operating around 5MHz.

Thanks. Much appreciated.

 

[Clifford Heath]

On 2/9/19 8:55 pm, Phil Hobbs wrote:

On 9/1/19 6:25 PM, Clifford Heath wrote:
On 31/8/19 4:37 pm, whit3rd wrote:
On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath
wrote:
On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier.
Does anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to
be hand-wired, but it gave the vacuum-tube vibrating reed
electrometers some real solid state competition on leakage current.
After all, if you bias a varactor at zero volts, what IS the
expected DC current?


That uses a pump signal at well above the signal frequency. It's
pretty hard to see how you could build an s-band amplifier that way.

When I was an undergrad, circa 1980-81, I had a research assistantship
with Professor Bill Shuter (radio astronomer and all-round good guy). He
had a millimeter-wave radio telescope that looked for carbon-12 and
carbon-13 monoxide emission at 115 and 110 GHz, respectively, for
probing the structure of interstellar giant molecular clouds.

The front end was a cooled parametric downconverter, followed by an
X-band GaAs FET IF amp, another downconverter, and a filter bank.  (FFTs
were still too slow in those days.)

Wow. But the question remains, does a TD/Varactor paramp need to be
pumped, or can it operate just by being biased into a negative
resistance region?

If pumped, wtf was that thing pumped with?

Clifford Heath.

 

[John Larkin]

On Tue, 3 Sep 2019 09:15:38 +1000, Clifford Heath <no.spam@please.net>
wrote:

On 2/9/19 8:55 pm, Phil Hobbs wrote:
On 9/1/19 6:25 PM, Clifford Heath wrote:
On 31/8/19 4:37 pm, whit3rd wrote:
On Friday, August 30, 2019 at 4:39:30 PM UTC-7, Clifford Heath
wrote:
On 9/8/19 2:52 am, bitrex wrote:
ather than varactors.

It's a curious thought though, using a varactor as an amplifier.
Does anyone have an example circuit?

The Philbrick (P2?) was earlier, but this one is well documented

https://archive.org/details/AnalogDevicesDataAcquisitionProductsCatalog1979/page/n97

The AD310 usually sat in a teflon-bushed socket and might have to
be hand-wired, but it gave the vacuum-tube vibrating reed
electrometers some real solid state competition on leakage current.
After all, if you bias a varactor at zero volts, what IS the
expected DC current?


That uses a pump signal at well above the signal frequency. It's
pretty hard to see how you could build an s-band amplifier that way.

When I was an undergrad, circa 1980-81, I had a research assistantship
with Professor Bill Shuter (radio astronomer and all-round good guy). He
had a millimeter-wave radio telescope that looked for carbon-12 and
carbon-13 monoxide emission at 115 and 110 GHz, respectively, for
probing the structure of interstellar giant molecular clouds.

The front end was a cooled parametric downconverter, followed by an
X-band GaAs FET IF amp, another downconverter, and a filter bank.  (FFTs
were still too slow in those days.)

Wow. But the question remains, does a TD/Varactor paramp need to be
pumped, or can it operate just by being biased into a negative
resistance region?

If pumped, wtf was that thing pumped with?

Clifford Heath.

There were some self-oscillating TD parametric amplifiers and
downconverters. TDs are basically gone, except for some back-diode RF
detectors.

A varactor amp needs a separate pump oscillator.




--

John Larkin Highland Technology, Inc trk

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com