What are the differences between wave generator and oscillator? (Specific design)

Thread Starter

itayd100

Joined Jan 30, 2016
3
Hello,

I design the attached circuit:
75 MHz Sine wave that connected to R and C in parallel


The output, the amplitude of the sine wave, is changing according to the C, more capacitance smaller amplitude of the sine wave.

When I tried that in the lab I got 2 results:
1. When I connected the signal generator as an oscillator I got the same results - higher C lower amplitude (of the sine wave in the output)
2. When I connected it to oscillator (http://www.farnell.com/datasheets/75480.pdf) I'm getting different result: the output is a sine wave, but if I make C higher the amplitude becoming lower until the sine wave (in the output) is "flipping" (kind of changing phase) and, if I keeping the C higher, the sine wave in the output getting higher

What are the differences between the two?
How can I make the oscillator work like the wave generator in this case?
 

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Dodgydave

Joined Jun 22, 2012
8,575
Its called Reactance, as the frequency changes the capacitor acts like a resistor in parallel and as the frequency increases its reactance gets lower, viceversa so it attenuates the signal.
 

Thread Starter

itayd100

Joined Jan 30, 2016
3
Its called Reactance, as the frequency changes the capacitor acts like a resistor in parallel and as the frequency increases its reactance gets lower, viceversa so it attenuates the signal.
Hey,
thanks for the answer. I know that called reactance, but why with the two setups I'm getting deference results? (same frequency, came C, same R)
 
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