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			Regular Guy
 
 
  Joined: 04 Jun 2017 Posts: 110
  
			
			 
			 
			
			
			
			
			
			
			
  
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				| Idiot Electronics Question | 
			 
			
				 Posted: Fri Feb 11, 2022 2:57 pm     | 
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				Resistor capacitor circuit.
 
 
Will the combo's they mention in the datasheet of a PIC run
 
 
by themselves? Without the PIC?
 
 
Just put a resistor and a capacitor on a breadboard.
 
 
We want to make a 'signal generator' for testing oscilloscopes.
 
 
Will R/C circuits run at khz frequencies like data sheet says?
 
 
200 khz and what not.
 
 
Thanks! _________________ PIC Hobbyist | 
			 
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			temtronic
 
 
  Joined: 01 Jul 2010 Posts: 9589 Location: Greensville,Ontario 
			
			 
			 
			
			
			
			
			
			
			
  
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				 Posted: Fri Feb 11, 2022 5:29 pm     | 
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				no
 
yes
 
BTW, there's an example program, comes with compiler, that would be IDEAL as an oscilloscope test pattern generator.... | 
			 
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			Ttelmah
 
 
  Joined: 11 Mar 2010 Posts: 19967
  
			
			 
			 
			
			
			
			
			
			
			
  
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				 Posted: Sat Feb 12, 2022 2:57 am     | 
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				As Jay says to the first bit. No.
 
 
The key is there has to be gain added somewhere. Things like RC circuits
 
all introduce losses. Put a signal in, and it'll come out the other end 
 
with some phase shift and reduction in the signal. To make it oscillate,
 
there has to be something to put back those losses. A simple transistor 
 
amplifier, or a op-amp.
 
Have a look here are the basic RC oscillator:
 
[url]
 
https://www.electronics-tutorials.ws/oscillator/rc_oscillator.html
 
[/url]
 
 
The PIC RC oscillator, is a simple charge discharge oscillator, not a 
 
sinusoidal oscillator. This can be done using a comparator (or even
 
easier an NE555). This won't give anything resembling a sine wave. | 
			 
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