Oscillator - Electronic Circuits Projects Diagrams Free

zefiris2K5 · 9th January 2006, 08:41 AM

Hi......
How to fine tune the output of the following oscillator?. Can I connect directly regulator circuit with the following circuit. From the experiment, it seems was a bad idea and the voltage output suddenly drop. Any suggestion are welcome....

akg · 9th January 2006, 09:00 AM

Quote:

Can I connect directly regulator circuit with the following

which regulator ckt..??

**Nigel Goodwin** · 9th January 2006, 09:48 AM

Assuming you want to prevent the massive distortion shown on your graph?, you need to add some kind of automatic gain control in the feedback path. This is commonly done using a special (expensive!) thermistor or a cheap incandescent light bulb. It can also be done using a FET circuit, or (crudely) with diode clipping.

If you google for 'wien bridge oscillator' you will find plenty of information and many circuits.

zefiris2K5 · 9th January 2006, 11:10 AM

I think there is nothing wrong with my drawing. The output looks like that. BTW, the incandescent light you mean, any torchlight bulb will do? And I'm experimenting it with my own regulator ckt. check below..... :roll:

**Nigel Goodwin** · 9th January 2006, 12:13 PM

Quote:

Originally Posted by zefiris2K5

BTW, the incandescent light you mean, any torchlight bulb will do?

No, it has to be fairly specific, usually very low current bulbs are used.

Quote:

And I'm experimenting it with my own regulator ckt. check below..... :roll:

I don't really see the relevance of that?, what is it supposed to do?, and where does it connect?. A wien bridge oscillator is a VERY old and common circuit, with many examples you can download off the internet, why not use a 'proper' method?.

spuffock · 9th January 2006, 12:18 PM

I hate to point this out, but your waveform implies that time reverses periodically ? ??

mstechca · 9th January 2006, 12:32 PM

I haven't used pins 4 and 8 of that particular amplifier.

It isn't normal for a waveform to go left when it is supposed to go right.
This should indicate that the oscillator isn't functioning correctly.

What kind of waveform are you trying to achieve?

zefiris2K5 · 9th January 2006, 02:30 PM

I need to build a cicuit to drive 2 motor. The speed of the 2nd motor dependent with the first motor. However I need to do some operation like comparator and etc. And to do this in analog domain I need AC signal, am I right? Then the oscillator is to serve that purpose. To drive motor, then I need to convert the AC signal into DC.

Quote:

No, it has to be fairly specific, usually very low current bulbs are used.

As for the bulb, how about this one? Is it OK?

Let me clarify the output, the output is like capacitor charging and discharging with +ve and -ve side execpt it kind of distort (maybe the gain to high).

**Nigel Goodwin** · 9th January 2006, 02:53 PM

Quote:

Originally Posted by zefiris2K5

I need to build a cicuit to drive 2 motor. The speed of the 2nd motor dependent with the first motor. However I need to do some operation like comparator and etc. And to do this in analog domain I need AC signal, am I right?

Your requirements are rather vague, but I wouldn't have thought so?.

Quote:

Then the oscillator is to serve that purpose. To drive motor, then I need to convert the AC signal into DC.

This sounds even stranger?. Are you using normal DC permanent magnet motors?.

Quote:

No, it has to be fairly specific, usually very low current bulbs are used.

As for the bulb, how about this one? Is it OK?

Possibly, but I (yet again) suggest you simply get a circuit off the internet, which will specify whatever gain system it uses. But as you're not wanting any quality (wien bridge oscillators are commonly used for very low distortion sinewaves), a simple diode clipping type circuit would be nmore than good enough.

Quote:

Let me clarify the output, the output is like capacitor charging and discharging with +ve and -ve side execpt it kind of distort (maybe the gain to high).

Yes, because you've left out the most vital part of the circuit, the automatic gain control.

But, from what you've said, I don't see as you have any need for an oscillator at all?.

Dr.EM · 9th January 2006, 04:24 PM

I have built this circuit and have found it to be more than good enough. I used polystyrene caps and ordinary resistors matched with a multimeter. It apparently uses a transistor as an AGC. That page explains a lot about how it works if nothing else, but I reccomend using the schematic so long as you don't need variable frequency.

http://home.att.net/~theremin1/Circu...scillator.html

audioguru · 9th January 2006, 07:10 PM

Texas Instruments has a pretty good applications note about many kinds of sine-wave oscillators. Their Wien bridge oscillator with a lightbulb for AGC has a serious error:

audioguru · 9th January 2006, 07:28 PM

Your "regulator" is a wonderful circuit to short the output of your "oscillator".
When the output attempts to go more positive than 8.9V, both diodes conduct and short the output.

Roff · 9th January 2006, 07:54 PM

Quote:

Originally Posted by audioguru

Texas Instruments has a pretty good applications note about many kinds of sine-wave oscillators. Their Wien bridge oscillator with a lightbulb for AGC has a serious error:

AG, that's a low-distortion, half-wave oscillator. :wink:

audioguru · 9th January 2006, 08:22 PM

[quote="Ron H"]

Quote:

Originally Posted by audioguru

AG, that's a low-distortion, half-wave oscillator. :wink:

Excellent! :lol:
TI sell ICs. They want you to make two circuits for each oscillator, one for each half of the sine-wave.

Roff · 9th January 2006, 08:25 PM

[quote="audioguru"]

Quote:

Originally Posted by Ron H

Quote:

Originally Posted by audioguru

AG, that's a low-distortion, half-wave oscillator. :wink:

Excellent! :lol:
TI sell ICs. They want you to make two circuits for each oscillator, one for each half of the sine-wave.

:lol: :lol: :lol:

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9th January 2006, 09:48 AM	(permalink)
Nigel Goodwin	Assuming you want to prevent the massive distortion shown on your graph?, you need to add some kind of automatic gain control in the feedback path. This is commonly done using a special (expensive!) thermistor or a cheap incandescent light bulb. It can also be done using a FET circuit, or (crudely) with diode clipping. If you google for 'wien bridge oscillator' you will find plenty of information and many circuits. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

9th January 2006, 12:18 PM	(permalink)
spuffock	I hate to point this out, but your waveform implies that time reverses periodically ? ??

9th January 2006, 12:32 PM	(permalink)
mstechca	I haven't used pins 4 and 8 of that particular amplifier. It isn't normal for a waveform to go left when it is supposed to go right. This should indicate that the oscillator isn't functioning correctly. What kind of waveform are you trying to achieve? __________________ -=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

9th January 2006, 04:24 PM	(permalink)
Dr.EM	I have built this circuit and have found it to be more than good enough. I used polystyrene caps and ordinary resistors matched with a multimeter. It apparently uses a transistor as an AGC. That page explains a lot about how it works if nothing else, but I reccomend using the schematic so long as you don't need variable frequency. http://home.att.net/~theremin1/Circu...scillator.html __________________ Angry!? I'm absolutely electrolytic! Will have to make do with myspace now I guess...