Need Help with Circuit design BAD!

Thread Starter

Jvietstylz

Joined Dec 2, 2006
2
I am an new engineering student and I cant figure out how to make a circuit with a blinking LED that stays on for ten second intervals. What I have so far is a circuit with two variable resistors, a resistor and an op amp. My led turns on and off already when I vary the resistor to cange the voltage accros them. How do I use capacitors and what calculations would I use to make it stay on for ten seconds.
Please Help
 

haditya

Joined Jan 19, 2004
220
ok what u need is a astable multivibrator.. its much easier to build using IC555 but since you dont have one no sweat, the same can be achieved using an opamp a few resistors and a capacitor
are you familiar with schmitt triggers?
 

Dave

Joined Nov 17, 2003
6,970
I am an new engineering student and I cant figure out how to make a circuit with a blinking LED that stays on for ten second intervals. What I have so far is a circuit with two variable resistors, a resistor and an op amp. My led turns on and off already when I vary the resistor to cange the voltage accros them. How do I use capacitors and what calculations would I use to make it stay on for ten seconds.
Please Help
You may be best uploading a schematic of your circuit as a reference.

Further to haditya's information, you may wish to look at Schmitt Triggers in the on-line textbook.

Dave
 
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