hi! need 512 khz oscillator ..

[jackson23]

512khz

hi again ..this is my last project in my school ...i have to make an oscillator 512 khz and ıf ıcant do ıt due to this morning( in here time is 2 :25) i cant pass and ı cant graduate ..please help... i have 741 opamp

 

[biff44]

khz oscillator

Well, there are probably a number of ways of doing it.

One way is to use the amplifier for its forward gain, and feedback a frequency selective signal from the output to input.

If the following two conditions are met, it will oscillate:
1) the round trip gain (forward gain + feedback loss) is greater than unity
2) the round trip phase shift wants to be 0 degrees ( or 360 degrees, depending on how you look at it).

I would set up the op amp for a positive voltgegain of something like 5. I would then feed back the op amp output back to the op amp input. The feedback network, for a simple low Q oscillator, might just be a series capacitor/inductor pair. If you select the values of the capacitor and inductor properly, the series pair will resonate (have zero impedance) at 512 KHz, and have a large inductive reactance above 512 KHz, and a large capacitive reactance below 512 KHz. Since the feedback path favors signals at 512 KHz over other frequencies, that is th frequency that the oscillations would build up at.

If you are physically building this oscillator, you may have to use a resitor divider tree to set the input DC voltage so that the output DC voltage is mid range. This will keep the op amp from pegging at the rails as the oscillations are starting.

Good luck!

 

[vfone]

https://www.ti.com/sc/docs/apps/msp/journal/aug2000/aug_07.pdf

 

[LvW]

hi again ..this is my last project in my school ...i have to make an oscillator 512 khz and ıf ıcant do ıt due to this morning( in here time is 2 :25) i cant pass and ı cant graduate ..please help... i have 741 opamp

If you don´t like coils - as proposed by BIF44 - google for WIEN OSCILLATOR.
It´s one of the simplest RC oscillator circuit. Frequency: 2*Pi*f=1/RC.
Good luck