Help with 741 opamp

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stevejnr

Joined Sep 8, 2011
3
Hi folks

I'm trying to create a voltage increase circuit using the 741 op amp in a non inverted configuration. This is the first curcuit I've ever made so I'm a complete novice...

So, I've got a small question. When I hook the op amp up to the supply, using a 12v dc computer supply with the GND/-12v?? connected to pin 4 and the +12v to pin 6 the volatage going in to pin 6 is 12.15V. However there is an output voltage on pin 6 of 11.53. Is this the correct characteristics of the opamp? How would I make the output 0, so that only the voltage I'm trying to increase is on the output?
 

MrChips

Joined Oct 2, 2009
30,720
You need a dual power supply, +12V and -12V.
Or replace the 741 opamp with one that will work on single supply, try LM324.
 

SgtWookie

Joined Jul 17, 2007
22,230
Hi stevejnr,

Sounds like you have the pins confused Pin 7 is the V+ supply, and pin 4 is the V- supply.

Here's an example circuit that is a "voltage follower"; basically, you get out what you put in:


If you want to increase the amplitude of the input signal, you use divided feedback with resistors. This is explained in our E-book, here:
http://www.allaboutcircuits.com/vol_3/chpt_8/5.html
 

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