EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Fantasma25 on February 11, 2014, 04:20:05 am
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Hello. I'm trying to make an overdrive effect for a guitar, but I want it to operate out of a single supply input. This is a basic clipper (overdrive) circuit with bipolar supply using a 741.
(http://imageshack.com/a/img199/1030/jolb.png)
In the simulation it works perfectly. Then, looking a little bit at an article by TI about single supply op amp design, I came up with this single supply circuit using a 318 op amp.
(http://imageshack.com/a/img849/285/mnzn.png)
The thing about this is that I'm placing a virtual ground (Vref) on the input and I'm not really sure that is a good idea. The simulation works perfectly as well with this one. Can anybody tell me if I'm doing the correct thing or something really wrong? Thanks!
Here is the simulation. The red one is the original and the green one is the modified one with the virtual ground. Thanks!!
(http://imageshack.com/a/img843/6923/n0n3.png)
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The proof of the pedal is in the pushing.
The circuit works fine but the 7805 chip has a quiescent current of 6-8mA. A simple voltage divider can create the virtual ground with just two resistors and a large valued bypass electrolytic cap, end up using much less battery current.