I'm sitting on a heap of germanium transistors. From the time that
computers made of discrete germanium transistors were decommissioned.
Also 10 mm and 6 mm ferrite core.
Can I make on oscillator, that runs on 1V , preferably using
coils ? (Also trying to use LTSpice for the first time.)
I can measure inductance of coils thanks to the miracle component
testers from China.

Groetjes Albert
--
Don't praise the day before the evening. One swallow doesn't make spring.
You must not say "hey" before you have crossed the bridge. Don't sell the
hide of the bear until you shot it. Better one bird in the hand than ten in
the air. First gain is a cat spinning. - the Wise from Antrim -

On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
albert@cherry.(none) (albert) wrote in
<nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:

>I'm sitting on a heap of germanium transistors. From the time that
>computers made of discrete germanium transistors were decommissioned.
>Also 10 mm and 6 mm ferrite core.
>Can I make on oscillator, that runs on 1V , preferably using
>coils ?

Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
Any LC oscillator will work.
Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?

In article <unbpba$35rk$1@solani.org>,
Jan Panteltje <alien@comet.invalid> wrote:
>On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
>albert@cherry.(none) (albert) wrote in
><nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
>
>>I'm sitting on a heap of germanium transistors. From the time that
>>computers made of discrete germanium transistors were decommissioned.
>>Also 10 mm and 6 mm ferrite core.
>>Can I make on oscillator, that runs on 1V , preferably using
>>coils ?
>
>Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
>Any LC oscillator will work.
>Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?

That sounds trivial. It is trivial. Not for me.
I need a schematic to build. Surely there must be some current into the base
for startup?

Groetjes Albert
--
Don't praise the day before the evening. One swallow doesn't make spring.
You must not say "hey" before you have crossed the bridge. Don't sell the
hide of the bear until you shot it. Better one bird in the hand than ten in
the air. First gain is a cat spinning. - the Wise from Antrim -

On Sunday, January 7, 2024 at 2:07:40 AM UTC+11, none albert wrote:
> In article <unbpba$35rk$1...@solani.org>,
> Jan Panteltje <al...@comet.invalid> wrote:
> >On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
> >albert@cherry.(none) (albert) wrote in
> ><nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
> >
> >>I'm sitting on a heap of germanium transistors. From the time that
> >>computers made of discrete germanium transistors were decommissioned.
> >>Also 10 mm and 6 mm ferrite core.
> >>Can I make on oscillator, that runs on 1V , preferably using
> >>coils ?
> >
> >Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
> >Any LC oscillator will work.
> >Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?
> That sounds trivial. It is trivial. Not for me.
> I need a schematic to build. Surely there must be some current into the base
> for startup?

You could try the Baxandall class-D oscillator

http://sophia-elektronica.com/Baxandall1959JM.pdf

but pay attention to the footnote on page 752. You'll have to chose turns ratios that give you enough base drive, but your should be able to put something together that runs from a 1V supply voltage if you are using germanium transistors.

Inverted transistors offer very low collector saturation voltage, so you might get away with less than a volt, if you swapped collector and emitters but you do need enough supply voltage to turn the bases on.

--
Bill Sloman, Sydney

On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
wrote:

>I'm sitting on a heap of germanium transistors. From the time that
>computers made of discrete germanium transistors were decommissioned.
>Also 10 mm and 6 mm ferrite core.
>Can I make on oscillator, that runs on 1V , preferably using
>coils ? (Also trying to use LTSpice for the first time.)
>I can measure inductance of coils thanks to the miracle component
>testers from China.
>
>Groetjes Albert

1v should be easy with a ge transistor.

People make oscillators that run off 10s of mV, but they usually use
jfets. A depletion phemt would be interesting.

Play with some ciruits in LTspice and post them here if you'd like us
to discuss them.

Is there an LT model of a germanium transistor?

Do you have an oscilloscope?

On Sat, 06 Jan 2024 14:50:17 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

>On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
>albert@cherry.(none) (albert) wrote in
><nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
>
>>I'm sitting on a heap of germanium transistors. From the time that
>>computers made of discrete germanium transistors were decommissioned.
>>Also 10 mm and 6 mm ferrite core.
>>Can I make on oscillator, that runs on 1V , preferably using
>>coils ?
>
>Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
>Any LC oscillator will work.
>Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?
>

Or something like this

https://ecstudiosystems.com/discover/textbooks/basic-electronics/oscillators/images/colpitts-oscillator.jpg

except it needs a power supply.

We were just discussing source-follower Colpitts oscillators yesterday
and concluded that we don't understand them.

On Sunday, January 7, 2024 at 3:05:04 AM UTC+11, John Larkin wrote:
> On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
> wrote:
> >I'm sitting on a heap of germanium transistors. From the time that
> >computers made of discrete germanium transistors were decommissioned.
> >Also 10 mm and 6 mm ferrite core.
> >Can I make on oscillator, that runs on 1V , preferably using
> >coils ? (Also trying to use LTSpice for the first time.)
> >I can measure inductance of coils thanks to the miracle component
> >testers from China.
>
> 1v should be easy with a ge transistor.
>
> People make oscillators that run off 10s of mV, but they usually use
> jfets. A depletion phemt would be interesting.
>
> Play with some ciruits in LTspice and post them here if you'd like us
> to discuss them.
>
> Is there an LT model of a germanium transistor?

https://grwhitehead.github.io/germaniumbjts/

Google is your friend.

<snipped silly question about an oscilloscope>

--
Bill Sloman, Sydney

albert <albert@cherry.(none)> wrote:

[...]

I realise this is completely off-topic but in your signature I see:
"First gain is a cat spinning. ". This is an expression I have never
heard before, could you tell me what it means?

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On Sat, 6 Jan 2024 16:45:37 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

>albert <albert@cherry.(none)> wrote:
>
>[...]
>
>I realise this is completely off-topic but in your signature I see:
>"First gain is a cat spinning. ". This is an expression I have never
>heard before, could you tell me what it means?

I can add one factoid: In Swedish (and perhaps all Nordic languages),
one literally says that a cat "spins" to say that it is purring.

Joe Gwinn

On 2024-01-06 11:03, John Larkin wrote:
> On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
> wrote:
>
>> I'm sitting on a heap of germanium transistors. From the time that
>> computers made of discrete germanium transistors were decommissioned.
>> Also 10 mm and 6 mm ferrite core.
>> Can I make on oscillator, that runs on 1V , preferably using
>> coils ? (Also trying to use LTSpice for the first time.)
>> I can measure inductance of coils thanks to the miracle component
>> testers from China.
>>
>> Groetjes Albert
>
>
> 1v should be easy with a ge transistor.
>
> People make oscillators that run off 10s of mV, but they usually use
> jfets. A depletion phemt would be interesting.
>
> Play with some ciruits in LTspice and post them here if you'd like us
> to discuss them.
>
> Is there an LT model of a germanium transistor?
>
> Do you have an oscilloscope?
>

One issue with old germanium transistors is that they have horrible base
leakage, enough to make the apparent beta negative in many cases.

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

On Sat, 6 Jan 2024 13:43:56 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>On 2024-01-06 11:03, John Larkin wrote:
>> On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
>> wrote:
>>
>>> I'm sitting on a heap of germanium transistors. From the time that
>>> computers made of discrete germanium transistors were decommissioned.
>>> Also 10 mm and 6 mm ferrite core.
>>> Can I make on oscillator, that runs on 1V , preferably using
>>> coils ? (Also trying to use LTSpice for the first time.)
>>> I can measure inductance of coils thanks to the miracle component
>>> testers from China.
>>>
>>> Groetjes Albert
>>
>>
>> 1v should be easy with a ge transistor.
>>
>> People make oscillators that run off 10s of mV, but they usually use
>> jfets. A depletion phemt would be interesting.
>>
>> Play with some ciruits in LTspice and post them here if you'd like us
>> to discuss them.
>>
>> Is there an LT model of a germanium transistor?
>>
>> Do you have an oscilloscope?
>>
>
>One issue with old germanium transistors is that they have horrible base
>leakage, enough to make the apparent beta negative in many cases.
>
>Cheers
>
>Phil Hobbs

I recall audio amps that had a cap coupling into the base with no bias
resistor. They amplified.

Betas were low, so people did beta-biased amps too. I suspect that
they twiddled the bias resistor until it worked, and then published.

I've done some arguably beta-biased circuits lately, with bipolars or
phemts.

On Sat, 06 Jan 2024 13:31:28 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:

>On Sat, 6 Jan 2024 16:45:37 +0000, liz@poppyrecords.invalid.invalid
>(Liz Tuddenham) wrote:
>
>>albert <albert@cherry.(none)> wrote:
>>
>>[...]
>>
>>I realise this is completely off-topic but in your signature I see:
>>"First gain is a cat spinning. ". This is an expression I have never
>>heard before, could you tell me what it means?
>
>I can add one factoid: In Swedish (and perhaps all Nordic languages),
>one literally says that a cat "spins" to say that it is purring.
>
>Joe Gwinn

There is actually an issued patent on using a laser pointer to make a
cat spin.

On Sat, 06 Jan 2024 11:09:57 -0800, John Larkin <jl@997PotHill.com>
wrote:

>On Sat, 06 Jan 2024 13:31:28 -0500, Joe Gwinn <joegwinn@comcast.net>
>wrote:
>
>>On Sat, 6 Jan 2024 16:45:37 +0000, liz@poppyrecords.invalid.invalid
>>(Liz Tuddenham) wrote:
>>
>>>albert <albert@cherry.(none)> wrote:
>>>
>>>[...]
>>>
>>>I realise this is completely off-topic but in your signature I see:
>>>"First gain is a cat spinning. ". This is an expression I have never
>>>heard before, could you tell me what it means?
>>
>>I can add one factoid: In Swedish (and perhaps all Nordic languages),
>>one literally says that a cat "spins" to say that it is purring.
>>
>>Joe Gwinn
>
>There is actually an issued patent on using a laser pointer to make a
>cat spin.

I recall such a patent, but it was to exercise the cat, who kept
trying to catch the moving laser spot on the floor, to no avail.

Don't think the frustrated cat was purring.

..<https://patents.google.com/patent/US5443036A/en>

Joe Gwinm

On 06/01/2024 16:45, Liz Tuddenham wrote:
> albert <albert@cherry.(none)> wrote:
>
> [...]
>
> I realise this is completely off-topic but in your signature I see:
> "First gain is a cat spinning. ". This is an expression I have never
> heard before, could you tell me what it means?

This, perhaps?

https://en.wikipedia.org/wiki/Buttered_cat_paradox

--
Cheers
Clive

On Sat, 6 Jan 2024 20:28:23 +0000, Clive Arthur
<clive@nowaytoday.co.uk> wrote:

>On 06/01/2024 16:45, Liz Tuddenham wrote:
>> albert <albert@cherry.(none)> wrote:
>>
>> [...]
>>
>> I realise this is completely off-topic but in your signature I see:
>> "First gain is a cat spinning. ". This is an expression I have never
>> heard before, could you tell me what it means?
>
>This, perhaps?
>
>https://en.wikipedia.org/wiki/Buttered_cat_paradox

I prefer cat with cream cheese.

Joe Gwinn <joegwinn@comcast.net> wrote:

> On Sat, 6 Jan 2024 16:45:37 +0000, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
>
> >albert <albert@cherry.(none)> wrote:
> >
> >[...]
> >
> >I realise this is completely off-topic but in your signature I see:
> >"First gain is a cat spinning. ". This is an expression I have never
> >heard before, could you tell me what it means?
>
> I can add one factoid: In Swedish (and perhaps all Nordic languages),
> one literally says that a cat "spins" to say that it is purring.

Could this be a reference to the rising and falling purring noise a
spinning wheel makes?

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On 1/6/24 17:13, John Larkin wrote:
> On Sat, 06 Jan 2024 14:50:17 GMT, Jan Panteltje <alien@comet.invalid>
> wrote:
>
>> On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
>> albert@cherry.(none) (albert) wrote in
>> <nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
>>
>>> I'm sitting on a heap of germanium transistors. From the time that
>>> computers made of discrete germanium transistors were decommissioned.
>>> Also 10 mm and 6 mm ferrite core.
>>> Can I make on oscillator, that runs on 1V , preferably using
>>> coils ?
>>
>> Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
>> Any LC oscillator will work.
>> Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?
>>
>
> Or something like this
>
> https://ecstudiosystems.com/discover/textbooks/basic-electronics/oscillators/images/colpitts-oscillator.jpg
>
> except it needs a power supply.
>
> We were just discussing source-follower Colpitts oscillators yesterday
> and concluded that we don't understand them.
>

To first order, it doesn't really matter which terminal you select
to be at AC GND.

The active device has gain -S*Ui*Zl, with Zl being a tank circuit.
Ui is derived from a tap on that tank, which allows you to work
out the loop gain. The loop gain needs to be unity at the tank
resonance. (Usually a bit greater, until some non-linearity at
large amplitude reduces it to unity.)

In the picture you referred to above, Zl is the series combination
of L and C2, with C1 in parallel across both. Ui is the voltage
across C2. They way it is drawn doesn't really help. It's the same
circuit, but I prefer to draw it like this:
+-----+-----+
| | |
L | |
| d |
+----g = C1
| s |
= C2 | |
| | |
+-----+-----+
Substitute cbe for dgs if you want, it's the same thing.

Jeroen Belleman

On Sat, 6 Jan 2024 21:43:27 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

>Joe Gwinn <joegwinn@comcast.net> wrote:
>
>> On Sat, 6 Jan 2024 16:45:37 +0000, liz@poppyrecords.invalid.invalid
>> (Liz Tuddenham) wrote:
>>
>> >albert <albert@cherry.(none)> wrote:
>> >
>> >[...]
>> >
>> >I realise this is completely off-topic but in your signature I see:
>> >"First gain is a cat spinning. ". This is an expression I have never
>> >heard before, could you tell me what it means?
>>
>> I can add one factoid: In Swedish (and perhaps all Nordic languages),
>> one literally says that a cat "spins" to say that it is purring.
>
>Could this be a reference to the rising and falling purring noise a
>spinning wheel makes?

I don't know the origin. Not German. Nor Icelandic (which is
basically Old Norse). But it is true in Norwegian, and Danish.

It may be a parallel to the sound of a well-tuned engine, which in
English we often describe as purring.

I'll think about it. Somewhere I have an old Swedish dictionary that
may have the etymology, or at least a clue.

An interesting rough parallel is that beer in German is Bier, but in
Swedish its öl. And oil in German is Öl, but in Swedish its olja.
Much of Swedish vocabulary is Germanic, so one's first guess would be
that the same word would be used in both. Norwegian and Danish also
do this.

Now there are many sayings that hold that beer is a social lubricant,
oiling the gears so to speak, and it may be that Swedish, Norwegian,
and Danish mutated to make the colloquial the standard word.
Basically, it appears to have been a Viking invention.

Joe Gwinn.

On Saturday, January 6, 2024 at 5:31:59 AM UTC-8, none albert wrote:
> I'm sitting on a heap of germanium transistors. From the time that
> computers made of discrete germanium transistors were decommissioned.
> Also 10 mm and 6 mm ferrite core.
> Can I make on oscillator, that runs on 1V , preferably using
> coils ? (Also trying to use LTSpice for the first time.)

Sure, you can make an oscillator; a one-transistor blocking oscillator
that saturates a magnetic core.
As for 'LTSpice' exercises, that's harder; the way a blocking oscillator
works, is by saturating the inductor metal.
That's completely a nonlinear process, doesn't fit the 'ideal transformer' model
at all. It requires a nonlinear inductor model...

On Sat, 6 Jan 2024 17:41:37 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

>On Saturday, January 6, 2024 at 5:31:59?AM UTC-8, none albert wrote:
>> I'm sitting on a heap of germanium transistors. From the time that
>> computers made of discrete germanium transistors were decommissioned.
>> Also 10 mm and 6 mm ferrite core.
>> Can I make on oscillator, that runs on 1V , preferably using
>> coils ? (Also trying to use LTSpice for the first time.)
>
>Sure, you can make an oscillator; a one-transistor blocking oscillator
>that saturates a magnetic core.
>As for 'LTSpice' exercises, that's harder; the way a blocking oscillator
>works, is by saturating the inductor metal.
> That's completely a nonlinear process, doesn't fit the 'ideal transformer' model
>at all. It requires a nonlinear inductor model...

It would be interesting to try to make a blocking oscillator with a
small old ge transistor and a 1-volt power supply.

On Sunday, January 7, 2024 at 12:41:42 PM UTC+11, whit3rd wrote:
> On Saturday, January 6, 2024 at 5:31:59 AM UTC-8, none albert wrote:
> > I'm sitting on a heap of germanium transistors. From the time that
> > computers made of discrete germanium transistors were decommissioned.
> > Also 10 mm and 6 mm ferrite core.
> > Can I make on oscillator, that runs on 1V , preferably using
> > coils ? (Also trying to use LTSpice for the first time.)
> Sure, you can make an oscillator; a one-transistor blocking oscillator
> that saturates a magnetic core.
> As for 'LTSpice' exercises, that's harder; the way a blocking oscillator
> works, is by saturating the inductor metal.
> That's completely a nonlinear process, doesn't fit the 'ideal transformer' model
> at all. It requires a nonlinear inductor model...

Which LTSpice offers, in the John Chan model. You can't use it directly in a transformer.

--
Bill Sloman, Sydney

On 1/6/2024 1:43 PM, Phil Hobbs wrote:
> On 2024-01-06 11:03, John Larkin wrote:
>> On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
>> wrote:
>>
>>> I'm sitting on a heap of germanium transistors. From the time that
>>> computers made of discrete germanium transistors were decommissioned.
>>> Also 10 mm and 6 mm ferrite core.
>>> Can I make on oscillator, that runs on 1V , preferably using
>>> coils ? (Also trying to use LTSpice for the first time.)
>>> I can measure inductance of coils thanks to the miracle component
>>> testers from China.
>>>
>>> Groetjes Albert
>>
>>
>> 1v should be easy with a ge transistor.
>>
>> People make oscillators that run off 10s of mV, but they usually use
>> jfets. A depletion phemt would be interesting.
>>
>> Play with some ciruits in LTspice and post them here if you'd like us
>> to discuss them.
>>
>> Is there an LT model of a germanium transistor?
>>
>> Do you have an oscilloscope?
>>
>
> One issue with old germanium transistors is that they have horrible base
> leakage, enough to make the apparent beta negative in many cases.
>
> Cheers
>
> Phil Hobbs
>

One time I inherited about a dozen that looked NOS from an audio repair
shop estate, unfortunately they all had internal shorts, maybe tin
whiskers.

On Saturday, January 6, 2024 at 7:57:30 PM UTC-8, bitrex wrote:
> On 1/6/2024 1:43 PM, Phil Hobbs wrote:
> > On 2024-01-06 11:03, John Larkin wrote:
> >> On Sat, 06 Jan 2024 14:31:49 +0100, albert@cherry.(none) (albert)
> >> wrote:
> >>
> >>> I'm sitting on a heap of germanium transistors. From the time that
> >>> computers made of discrete germanium transistors were decommissioned.
> >>> Also 10 mm and 6 mm ferrite core.
> >>> Can I make on oscillator, that runs on 1V , preferably using
> >>> coils ? (Also trying to use LTSpice for the first time.)
> >>> I can measure inductance of coils thanks to the miracle component
> >>> testers from China.
> >>>
> >>> Groetjes Albert
> >>
> >>
> >> 1v should be easy with a ge transistor.

> >> Is there an LT model of a germanium transistor?

> > One issue with old germanium transistors is that they have horrible base
> > leakage, enough to make the apparent beta negative in many cases.
> >

> One time I inherited about a dozen that looked NOS from an audio repair
> shop estate, unfortunately they all had internal shorts, maybe tin
> whiskers.

I've certainly seen Ge transistors fail with very low breakdown voltages.
Totally normal transistor operation below 4V collector bias...
The leakage problem might be a rediffusion of dopants, or micro fracture
growth. There wasn't a lot of tin in those packages, but base thinning
was discussed (better HF response and lower breakdown voltages being
the age indicators).

On a sunny day (Sat, 6 Jan 2024 23:15:07 +0100) it happened Jeroen Belleman
<jeroen@nospam.please> wrote in <uncjc2$p3ru$1@dont-email.me>:

>On 1/6/24 17:13, John Larkin wrote:
>> On Sat, 06 Jan 2024 14:50:17 GMT, Jan Panteltje <alien@comet.invalid>
>> wrote:
>>
>>> On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
>>> albert@cherry.(none) (albert) wrote in
>>> <nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
>>>
>>>> I'm sitting on a heap of germanium transistors. From the time that
>>>> computers made of discrete germanium transistors were decommissioned.
>>>> Also 10 mm and 6 mm ferrite core.
>>>> Can I make on oscillator, that runs on 1V , preferably using
>>>> coils ?
>>>
>>> Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
>>> Any LC oscillator will work.
>>> Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?
>>>
>>
>> Or something like this
>>
>> https://ecstudiosystems.com/discover/textbooks/basic-electronics/oscillators/images/colpitts-oscillator.jpg
>>
>> except it needs a power supply.
>>
>> We were just discussing source-follower Colpitts oscillators yesterday
>> and concluded that we don't understand them.
>>
>
>To first order, it doesn't really matter which terminal you select
>to be at AC GND.
>
>The active device has gain -S*Ui*Zl, with Zl being a tank circuit.
>Ui is derived from a tap on that tank, which allows you to work
>out the loop gain. The loop gain needs to be unity at the tank
>resonance. (Usually a bit greater, until some non-linearity at
>large amplitude reduces it to unity.)
>
>In the picture you referred to above, Zl is the series combination
>of L and C2, with C1 in parallel across both. Ui is the voltage
>across C2. They way it is drawn doesn't really help. It's the same
>circuit, but I prefer to draw it like this:
> +-----+-----+
> | | |
> L | |
> | d |
> +----g = C1
> | s |
> = C2 | |
> | | |
> +-----+-----+
>Substitute cbe for dgs if you want, it's the same thing.

When frequencies get higher:
https://panteltje.online/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
panteltje.online/pub/twisted_wire_oscillator_IMG_6629.JPG
John Larking may like that :-)
But the OP's Ge transistors will likely not go that high.

On a sunny day (Sat, 06 Jan 2024 16:07:25 +0100) it happened
albert@cherry.(none) (albert) wrote in
<nnd$6c23b994$17dc2f93@4e33c84aa30fc7d3>:

>In article <unbpba$35rk$1@solani.org>,
>Jan Panteltje <alien@comet.invalid> wrote:
>>On a sunny day (Sat, 06 Jan 2024 14:31:49 +0100) it happened
>>albert@cherry.(none) (albert) wrote in
>><nnd$30302dcf$1e37b7a5@bbcc4a9e0386ea66>:
>>
>>>I'm sitting on a heap of germanium transistors. From the time that
>>>computers made of discrete germanium transistors were decommissioned.
>>>Also 10 mm and 6 mm ferrite core.
>>>Can I make on oscillator, that runs on 1V , preferably using
>>>coils ?
>>
>>Yes, Ge transistors start conducting from 150 mV Vbe to maybe 300 mV, so much less than Si .7 V,
>>Any LC oscillator will work.
>>Tuned circuit LC in the collector, feedback 1 turn (correct phase) to the base?
>
>That sounds trivial. It is trivial. Not for me.
>I need a schematic to build. Surely there must be some current into the base
>for startup?
>
>Groetjes Albert

https://panteltje.online/pub/8052AH_BASIC_computer/dc_dc_converter_detail/5V_to_30V_converter.jpg