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jfeng@my-deja.com
Guest

Mon Oct 29, 2018 3:45 pm   



On Monday, October 29, 2018 at 5:34:29 AM UTC-7, jurb...@gmail.com wrote:
Quote:
The vibrator in an old car radio. Not only does it oscillate without
transistors or tubes, some rectify without diodes. A second set of contacts
make for a synchronous rectifier.
If you ever opened one, you would find it is basically an electromagnet configured as a buzzer, just like the one you probably built in grade school science or shop class, and just like the one you mentioned a couple weeks ago.



Guest

Mon Oct 29, 2018 7:45 pm   



On Monday, October 29, 2018 at 5:34:29 AM UTC-7, jurb...@gmail.com wrote:
> The vibrator in an old car radio. Not only does it oscillate without transistors or tubes, some rectify without diodes. A second set of contacts make for a synchronous rectifier.

Amazing!
https://en.wikipedia.org/wiki/Vibrator_(electronic)

How long did they last? A year or so?

Thanks!

Michael

Phil Hobbs
Guest

Mon Oct 29, 2018 8:45 pm   



On 10/28/2018 10:40 PM, amdx wrote:
Quote:
On 10/17/2018 2:33 PM, mrdarrett_at_gmail.com wrote:
Hello,

What are some examples of oscillators which don't require transistors
or vacuum tubes?

So far I found relay oscillators and the Pearso There n-Anson oscillator.

Does the Pearson-Anson oscillator require a high-voltage neon lamp, or
would it work on LEDs as well?
https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect

Relay oscillators look neat too but I don't imagine they would last
very long at high frequencies.
https://www.youtube.com/watch?v=WuG4nOyF99s

Thanks,

Michael


  There used to be signs that used movement to get attention, it could
be as simple as a waving hand. The hand was setup as a pendulum and when
the battery was installed you could give it a push, this would close a
switch, energizing the solenoid and giving the pendulum a kick this
would also open the switch. The pendulum would go through its swing and
then come back and close the switch, repeating the cycle.
 I searched but could not fid a sign or a circuit, but I'm sure there is
one somewhere online.
 Variation of the relay oscillator.


The really fun one was the box with a trap door on top and a big toggle
switch on the front. When you turned on the switch, a motor whirred and
a plastic hand came out of the box, turned the switch off again, then
went back into the box before the motor actually turned off.

I had a piggy bank that worked like that--you put the coin in a shallow
slot with two contacts at the bottom. The coin completed the circuit,
and the hand came out and collected the coin.

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
https://hobbs-eo.com


Guest

Mon Oct 29, 2018 9:45 pm   



On Monday, October 29, 2018 at 1:01:10 PM UTC-7, Jasen Betts wrote:
Quote:
On 2018-10-29, mrdarrett_at_gmail.com <mrdarrett_at_gmail.com> wrote:
On Monday, October 29, 2018 at 5:34:29 AM UTC-7, jurb...@gmail.com wrote:
The vibrator in an old car radio. Not only does it oscillate without transistors or tubes, some rectify without diodes. A second set of contacts make for a synchronous rectifier.

Amazing!
https://en.wikipedia.org/wiki/Vibrator_(electronic)

How long did they last? A year or so?

a car won't last a year if operated continuously: at 60 km/h that would be
half a million kilometers

I had one in my car for a couple of years and never had a problem.
that was maybe 400 operating hours.

I expect they got a couple of thousand hours out of those units about
the same as we see quoted for cheap electrolytic capacitors and LEDs.



--
When I tried casting out nines I made a hash of it.


2000 hours! That durable, huh!

Jasen Betts
Guest

Mon Oct 29, 2018 9:45 pm   



On 2018-10-29, mrdarrett_at_gmail.com <mrdarrett_at_gmail.com> wrote:
Quote:
On Monday, October 29, 2018 at 5:34:29 AM UTC-7, jurb...@gmail.com wrote:
The vibrator in an old car radio. Not only does it oscillate without transistors or tubes, some rectify without diodes. A second set of contacts make for a synchronous rectifier.

Amazing!
https://en.wikipedia.org/wiki/Vibrator_(electronic)

How long did they last? A year or so?


a car won't last a year if operated continuously: at 60 km/h that would be
half a million kilometers

I had one in my car for a couple of years and never had a problem.
that was maybe 400 operating hours.

I expect they got a couple of thousand hours out of those units about
the same as we see quoted for cheap electrolytic capacitors and LEDs.



--
When I tried casting out nines I made a hash of it.


Guest

Tue Oct 30, 2018 3:45 am   



>"and just like the one you mentioned a couple weeks ago. "

Yeah but I forgot about the synchronous rectifier part. Not only no transistor or tubes, no diodes either of any "state".

Cursitor Doom
Guest

Tue Oct 30, 2018 7:45 pm   



On Sun, 28 Oct 2018 21:40:50 -0500, amdx wrote:

Quote:
There used to be signs that used movement to get attention, it could
be as simple as a waving hand. The hand was setup as a pendulum and when
the battery was installed you could give it a push, this would close a
switch, energizing the solenoid and giving the pendulum a kick this
would also open the switch. The pendulum would go through its swing and
then come back and close the switch, repeating the cycle.


Sounds grossly inefficient. I'm reminded of those Chinese cat things with
the waving paw. They seem to have got battery life down to a fine art;
must be using a 'joule thief' or some variant thereof I would imagine.




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This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

default
Guest

Wed Oct 31, 2018 5:45 pm   



On Tue, 30 Oct 2018 18:30:08 -0000 (UTC), Cursitor Doom
<curd_at_notformail.com> wrote:

Quote:
On Sun, 28 Oct 2018 21:40:50 -0500, amdx wrote:

There used to be signs that used movement to get attention, it could
be as simple as a waving hand. The hand was setup as a pendulum and when
the battery was installed you could give it a push, this would close a
switch, energizing the solenoid and giving the pendulum a kick this
would also open the switch. The pendulum would go through its swing and
then come back and close the switch, repeating the cycle.

Sounds grossly inefficient. I'm reminded of those Chinese cat things with
the waving paw. They seem to have got battery life down to a fine art;
must be using a 'joule thief' or some variant thereof I would imagine.


The so-called joule thief is what was called a blocking oscillator
back in the days of vacuum tubes and you could find one in every tube
type TV. The flyback pulse produces a high voltage because the
tube/transistor is cut off abruptly, and the collapsing field produces
a voltage spike.

Those moving display gizmos were neat, I used to play with them as a
kid. A single D battery or pair of them could keep the thing swinging
for a week or two. The magnet was on a half-circle of wire and
suspended so it would pass through the coil, working a leaf-switch of
a couple of phosphor bronze springs that would repel the magnet as it
passed the midpoint. What is impressive was the length of time they's
keep working - particularly with the zinc carbon batteries we had in
those days.

Transistors cost money back then too. My first blocking oscillator
using transistors was pulled from a Radio Electronics magazine for a
"sonic shake table" (an interesting gizmo that could make standing
waves in particles of flour in an upturned speaker cone - or mercury
if you happen to have some) When I got tired of playing with it, I
added it to my bicycle for a horn and ran it off the hub mounted
alternator.

Don Kuenz
Guest

Tue Nov 13, 2018 6:45 am   



default <default_at_defaulter.net> wrote:
Quote:
On Wed, 17 Oct 2018 12:33:19 -0700 (PDT), mrdarrett_at_gmail.com wrote:

Hello,

What are some examples of oscillators which don't require transistors or vacuum tubes?

So far I found relay oscillators and the Pearson-Anson oscillator.

Does the Pearson-Anson oscillator require a high-voltage neon lamp, or would it work on LEDs as well?
https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect

Relay oscillators look neat too but I don't imagine they would last very long at high frequencies.
https://www.youtube.com/watch?v=WuG4nOyF99s

When I was in high school I built this rather elaborate relay
oscillator to dial a pulse type telephone. One relay developed
pulses, another was rigged as a monostable to time the pulse train to
dial a particular number. A rotary stepper relay could read the holes
in cards and cycle through some crude punch cards to dial (worked but
not well)

Scr's can be made to oscillate, of course unijunctions, some negative
resistance diodes like tunnel/gunn, electro-mechanical toys using
magnets and leaf/reed switches or transistors to energize coils,
old-time magnetic earphones and carbon mikes to develop feedback,
tuning forks with feedback drivers, propagation delay devices, arc
lights, early radio transmitters that used motors driving many-pole
alternators, spark-excited Tesla coils...


Was your high school project an electronic vibrator?

https://en.wikipedia.org/wiki/Vibrator_(electronic)

Thank you, 73,

--
Don Kuenz KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

default
Guest

Tue Nov 13, 2018 1:45 pm   



On Tue, 13 Nov 2018 04:50:22 -0000 (UTC), Don Kuenz <g_at_crcomp.net>
wrote:

Quote:
default <default_at_defaulter.net> wrote:
On Wed, 17 Oct 2018 12:33:19 -0700 (PDT), mrdarrett_at_gmail.com wrote:

Hello,

What are some examples of oscillators which don't require transistors or vacuum tubes?

So far I found relay oscillators and the Pearson-Anson oscillator.

Does the Pearson-Anson oscillator require a high-voltage neon lamp, or would it work on LEDs as well?
https://en.wikipedia.org/wiki/Pearson%E2%80%93Anson_effect

Relay oscillators look neat too but I don't imagine they would last very long at high frequencies.
https://www.youtube.com/watch?v=WuG4nOyF99s

When I was in high school I built this rather elaborate relay
oscillator to dial a pulse type telephone. One relay developed
pulses, another was rigged as a monostable to time the pulse train to
dial a particular number. A rotary stepper relay could read the holes
in cards and cycle through some crude punch cards to dial (worked but
not well)

Scr's can be made to oscillate, of course unijunctions, some negative
resistance diodes like tunnel/gunn, electro-mechanical toys using
magnets and leaf/reed switches or transistors to energize coils,
old-time magnetic earphones and carbon mikes to develop feedback,
tuning forks with feedback drivers, propagation delay devices, arc
lights, early radio transmitters that used motors driving many-pole
alternators, spark-excited Tesla coils...

Was your high school project an electronic vibrator?

https://en.wikipedia.org/wiki/Vibrator_(electronic)

Thank you, 73,


No but some years later I made a small air pump using a coil driving a
magnet. Other than the heat it developed, it might have made a decent
vibrator (of the sex toy variety).

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