Hi. I was listening to a power supply buzzing away and I wondered if i could use this unwanted characteristic of some voltage regulators to oscillate,to pulse a coil and this is what I came up with.
I used a TS 2950 3.3v voltage regulator, a coil and an Led and it worked.The input voltage is quite important to get the TS2950 oscillating,it needs to be between 1.35 and 1.5v when using the circuit in its simplest form but the input voltage range can be widened by adding a cap and resistor.
By using a 1:1 bifiar coil,you can also charge a battery or cap but what is interesting about this circuit is it does not drain a battery at all,even after a 4 day continous run,not even 1 millivolt and the output voltage when using the bifilar coil is a lot higher than the input voltage or output of the voltage regulator.
I cannot measure any amp draw at all across a 1 ohm resistor and can only get a reading when using a series amp meter of 84uA but i dislike adding meters in series as they can become part of the circuit but the TS2950 has a Quiescent current draw of 75uA which is the current used by the regulators internal circuitry and is not available to the load but this is when the regulator is running under normal conditions but i am not running it in normal mode but in resonance,oscilating mode so it is a whole different ball game..
I have not done much experimenting with this yet but I can say that there is something very unusual about this circuit and I would be interested to hear what you think.
Here is a vid and circuit diagrams.Jonny

(http://img207.imageshack.us/img207/6787/voltageregulatoroscilla.th.jpg)

(http://img717.imageshack.us/img717/6787/voltageregulatoroscilla.th.jpg)

http://www.youtube.com/watch?v=fRWmurlMX9U

Here is a replication by Lidmotor.

http://www.youtube.com/watch?v=Axsd1SGmnXc

Hi. I was listening to a power supply buzzing away and I wondered if i could use this unwanted characteristic of some voltage regulators to oscillate,to pulse a coil and this is what I came up with.
I used a TS 2950 3.3v voltage regulator, a coil and an Led and it worked.The input voltage is quite important to get the TS2950 oscillating,it needs to be between 1.35 and 1.5v when using the circuit in its simplest form but the input voltage range can be widened by adding a cap and resistor.
By using a 1:1 bifiar coil,you can also charge a battery or cap but what is interesting about this circuit is it does not drain a battery at all,even after a 4 day continous run,not even 1 millivolt and the output voltage when using the bifilar coil is a lot higher than the input voltage or output of the voltage regulator.
I cannot measure any amp draw at all across a 1 ohm resistor and can only get a reading when using a series amp meter of 84uA but i dislike adding meters in series as they can become part of the circuit but the TS2950 has a Quiescent current draw of 75uA which is the current used by the regulators internal circuitry and is not available to the load but this is when the regulator is running under normal conditions but i am not running it in normal mode but in resonance,oscilating mode so it is a whole different ball game..
I have not done much experimenting with this yet but I can say that there is something very unusual about this circuit and I would be interested to hear what you think.
Here is a vid and circuit diagrams.Jonny

(http://img207.imageshack.us/img207/6787/voltageregulatoroscilla.th.jpg)

(http://img717.imageshack.us/img717/6787/voltageregulatoroscilla.th.jpg)

http://www.youtube.com/watch?v=fRWmurlMX9U

Here is a replication by Lidmotor.

http://www.youtube.com/watch?v=Axsd1SGmnXc

Good Morning
Thanks for sharing this. These could be teh oscillators I have been looking for.
Bizzy

@Tito and Bizzy.Thanks for looking .I hope it helps you in your experiments.
@dimbulb.Thanks.The current draw is very low and to still get 2V steady output is a head scratcher and you can replace the led with a 4148 diode and charge another cap,I have done this today and a few other things so stay tuned.
Regarding waveforms.I do not have a clue what it looks like but I would love to know.I only have decent multimeters and work from my kitchen,much to my wife's anoyance but I keep telling her it's in the name of science and besides,when you need that certain thingy me bob for an experiment,9 times out of 10,you can find it in your kitchen cupboard but I am kind of hoping someone here,more experienced than me could fill us in on the wave.
The voltage I used was a AA battery @ 1.46v and it was still at that voLtage 4 days later and I had the meter reading to 3 decimal places.
The current draw is 83uA,read with the amp meter in series.I can't get a reading,measured across a 1 ohm resistor which is my preferred measuring method.The Current draw can be increased by using different value resistors and coils.
The interesting thing about Voltage regulators is that they are all made different so there could be a lot more things to discover yet.Thanks for your interest.Jonny

 

Here is the internals of the IC    It has a cap as I suspected in order for Jonny to get the 2v out . ;]

Very interesting data on this IC   maybe the 3v vs the 3.3v may show better effects.  Jon  Was the 5v any diff from the 3.3v in quality of output as you have shown? Any diff?

Thanks for showing.  Your finds are always a pleasure to experience. ;]

Mags

Hey Jonny 

Ill do some screen shots of the pdf this evening and post the specs as jpeg pics, as others may have the same issue.   

Mags

haha..
you need to look here..  http://www.energeticforum.com/renewable-energy/7410-simple-voltage-regulator-oscillator.html

we all look at to many forums and get confused sometimes..
he doesn't post here under his lidmotor name..

robbie

ps.. the L4931 with a drop out voltage of 0.4v doesn't work..

All,

The National Semiconductor Applications Note on the original LM78xx
regulator showed how to build a switching regulator by adding only
an inductor to this three terminal voltage regulator, to increase it's
regulation efficiency. So I think rational astable operation will
generally be a competitive attribute of any three terminal regulator.

:S:MarkSCoffman