Oscillator

S

soundman

New Member
Hey Guys.

I have a 12V, 0, -12V split power supply as part of my design. Is there any Oscillator chip to work within That voltage? The output must be either sine or Square wave with an accurate 50% duty cycle. The final freq of the Oscillator is 80 kHz to 100 kHz.

Any suggestion please?

Thank.
 
For square and sine you need totally different types of oscillators but a sinewave can easily be converted to a square. A square can be converted to a sine but it's complicated unless the frequency doesn't change much.

A comparator can be configured as a Schmitt trigger oscillator to produce a square wave.

A high speed op-amp can be configured as a wein bridge oscillator and will work at 100kHz but will require a dual ganged pot.

You could build an LC oscillator and an AM radio tuning capacitor.
 

hi
Are you saying you want a +/-12V square or sine wave or is that just the bench supply voltages.??
 
An XR2206 function generator IC is still being manufactured and has a max supply of 26V single, or plus and minus 13V. It has sine-wave and square-wave outputs up to 100khz with low sine-wave distortion.
 

I just want EITHER Sine or square waveform with Exactly 50% duty cycle.

Can I generate 50% of duty cycle by an OP-AMP As an oscillator?
 
ericgibbs said:
hi
Are you saying you want a +/-12V square or sine wave or is that just the bench supply voltages.??
Click to expand...

My power Supplier is +/-!2V.
I was thinking of CMOS 40XX multivibrator Oscillator chips, but I am not able to handle it by my this said power supply, I specially fear to not know how to connect them to each other and Totally do not know how to do it and if the performance of doing so will be ok?
 
If it needs to be exactly 50% then you could use a divide by 2 counter but the maximum voltage of most ICs is 18V you need to power the IC from -12V and use a buffer transistor to switch the +12V load.
 
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That will work but how can you be sure or the frequency or the 50% duty cycle?
 
Hero999 said:
That will work but how can you be sure or the frequency or the 50% duty cycle?
Click to expand...

Well it has a good sinusoidal output so it depends on where you set the threshold.

edit*

One thing he could do is super-impose it on a DC level.
 
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Space Varmint said:
Well it has a good sinusoidal output.
Click to expand...
No.
Maybe its output is a sine-wave at RF frequencies because the transistor is so slow. But at audio frequencies its output is a saturated square-wave because it has nothing to limit its max amplitude.
 
Very simple square wave generator adjust for 50% with voltage to pins 3&6 on the first one, ignore the voltage double half.
Here's some of the one I like, all copied off the Web
Kinarfi
 

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Last edited:
The problem with phase shift is you have to adjust the value of more than one resistor.

Another option is to use a triangle wave generator and add a shaper circuit to get a sinewave generator which can be adjusted by varying the value of one pot.

I have a schematic but I think it's on my Linux partition and I'm currently logged on to Windows. I'll post it tomorrow.
 
audioguru said:
No.
Maybe its output is a sine-wave at RF frequencies because the transistor is so slow. But at audio frequencies its output is a saturated square-wave because it has nothing to limit its max amplitude.
Click to expand...

When was the last time ypou made one? I have yet to see one saturate though it does have to do with the way you bias it. So I am sure you could make it happen. But really, it puts out a very pretty 50 / 50 cycle and the transistor I have in the example is better at audio and VLF. You could use any transistor. I was just giving the guy a somple oscillator circuit anyway. Seemed everybody just wanted to ask him a bunch of questions so I gave him something to work with.
 
kinarfi said:
Very simple square wave generator adjust for 50% with voltage to pins 3&6 on the first one, ignore the voltage double half.
Here's some of the one I like, all copied off the Web
Kinarfi
Click to expand...

That's a good one. How about this very simple square wave oscillator:

The problem with it is the 12 volts but he could follow it up with an amplifier.
 

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I don't make garbage circuits. I make a sine-wave oscillator with additional circuitry that stabilizes its output so it doesn't saturate which makes a square-wave.
Your simple circuit is a square-wave oscillator not a sine-wave oscillator.
 
audioguru said:
I don't make garbage circuits. I make a sine-wave oscillator with additional circuitry that stabilizes its output so it doesn't saturate which makes a square-wave.
Your simple circuit is a square-wave oscillator not a sine-wave oscillator.
Click to expand...

I would love nothing more than to agree with you Audio. But it is a sine-wave a oscillator. It's an Armstrong oscillator and really it puts out a pretty sine wave. It's just not vary stable but it is powerful!
 
I've tried simulating it and it gives pules.

Simulators can be wrong of course, what values did you use? I guessed.

For some reason I couldn't attach the .asc file so here it is:
Code: 
Version 4
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WIRE 256 -160 256 -192
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WIRE 544 -96 544 -128
WIRE 592 -80 592 -240
WIRE 256 -64 256 -80
WIRE 368 -32 368 -64
WIRE 464 -32 464 -240
WIRE 464 -32 368 -32
WIRE 528 -32 464 -32
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WIRE 592 32 592 16
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SYMATTR InstName V1
SYMATTR Value 12V
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SYMATTR InstName Q1
SYMATTR Value 2N3055
SYMBOL Misc\\EuropeanResistor 352 -160 R0
SYMATTR InstName R1
SYMATTR Value 470R
SYMBOL Misc\\EuropeanResistor 352 -16 R0
SYMATTR InstName R2
SYMATTR Value 470R
SYMBOL Misc\\EuropeanPolcap 528 -192 R0
SYMATTR InstName C2
SYMATTR Value 1µ
TEXT 720 -136 Left 0 !.tran 5m
TEXT 720 -104 Left 0 !.param N=10
TEXT 728 -40 Left 0 !k1 L1 L2 L3 1
TEXT 720 -72 Left 0 !.param Lp=470u Ls=470u
 

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Thanks to all suggestions,

After reading your suggestions I came to this conclusion that working with CMOS chips as an Square wave producer circuitry (or those cmos multivibrator chips, Do you guys know any?) is the best choice because they are assembled easily and are really trustable.
So the Attached picture shows the main problem which I am dealing with.
I have serious problems to understand how to do so. My only guess is that maybe a capacitor between the single ended stage and the doubled stage is able to help to set the output signal of the cmos chip to zero, and thus gives a suitable signal for the last doubled stage? If so, Then what about the efficiency of this circuitry than a normal doubled circuit instead of 40XX?
Any paper to enlighten me about how to connect a single ended circuit to a doubled powered one, Pros and Cons, would be really aplicated.
 

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Last edited:
You still really haven't provided enough information.

Do you want to switch the low/high side?

Do you need a pulse with at +/-12V?

Or do you need to switch an h-bridge?
 
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