Op-Amp as oscillator

269

02:30:29

Here, U can understand the basic working of Op-Amp as simple oscillator.. Hw it can generate oscillating output signals.. hw it is amplifying input signal is shown in the circuit...
Here non-inverting configuration is used...
So and also Rf and R1 are same... So gain of amp is 2...

So from this u can also clerify that it is not always that gain is unity of oscillator... In fact.. gain around loop/feedback should be greater or equal then unity.... So that concept is also clear... Phase shift is zero because series RC produced +45° phase shift where as parallel RC produced -45° phase shift.. and non inverting configuration produces 0° phase shift... So overall phase shift is 0° which is integral multiple of 2π which is second necessary condition of oscillator...

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published 9 years ago

thebugger

9 years ago

You need a stronger positive feedback, and also remove the AC source, it doesn't match the resonant frequency anyway (it's around 160Hz). Also if you want it amplitude stabilised, you need some sort of AGC feedback.

vishal001chavda

9 years ago

Correct.. bt m trying to show only basics of working... Hw it can amplify as well as produce ac signal... AGC would be difficult to understand in basic learning concepts..

thebugger

9 years ago

An incandescent bulb AGC is easily comprehensible, when explained properly, but EC can't emulate the PTC of a bulb

hurz

9 years ago

Its a wien bridge and does need a exact gain of 3! 3 is the point were the bridge is proper aligned at 159.15......Hz http://everycircuit.com/circuit/6550200820957184

vishal001chavda

9 years ago

I have removed the portion of wein bridge... As whole this circuit would be in branch of wein bridge.. here m just producing ac wave at 159khz.. so no need to adjust gain... Also i will make one circuit that would include incandescent bulb

hurz

9 years ago

Its 159.15... Hz and not kHz were the bridge divides the input voltage by 3!

thebugger

9 years ago

I suggest you try a diode stabilisation circuit, bulbs don't work this way here is EC.

hurz

9 years ago

As long he dont understand the basics of this circuit, it doesn't make any sense to discuss AGC and amplitude stabilisation.

thebugger

9 years ago

Depends, AGC is not a hard concept to grasp, even for newbies... If explained properly.

vishal001chavda

9 years ago

AGC and AFC are the not basic thing which is related to working of OP-AMP.. If you are showing the working of ic.. for that purpose.. there is no need of showing agc.. remember.. here application is not important.. the working is... Once working is clear.. application can be made using ic.. just like how thermistor is working for temperature measurements....

chrissally

9 years ago

good

hurz

9 years ago

And this oscillator does not even oscillates, cuz of wrong gain. You just demostrate you have no idea how this oscillator has to be configured to have chance to work. So better not talking about AGC if the basics are missing on your side.

vishal001chavda

9 years ago

My frnd such arrogance is not good for skill growth... And also for developed skill.. it resist further improvement..

hurz

9 years ago

"Oscillator does not oscillates" = "arrogance"? "Wrong gain of 2" = "arrogance"? vishal001chavda = ignorant, true.

thebugger

9 years ago

Actually to be fair, the circuit is wired correctly, it just lacks the correct component values. It won't oscillate as it is, but it will act as an active bandpass filter. So yeah, the circuit is wired correctly, but it's not an oscillator yet

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