regulator

[lee9587]

i have an lm741 in my project and i am wondering if i can use +9,-9 instead of the maximum rating???also i have an external -12v source and i am wondering is it as simple as using an lm7809 to bring this to -9v or would i have a problem with over heating??

thanks

 

[ericgibbs]

i have an lm741 in my project and i am wondering if i can use +9,-9 instead of the maximum rating???also i have an external -12v source and i am wondering is it as simple as using an lm7809 to bring this to -9v or would i have a problem with over heating??

thanks

hi,
A 741 will work OK with +/-9V supplies.

The Vout will only swing to about +/-2.5V of the rail voltage, using +/-9V this will be approx +/-6.5V

 

[crutschow]

The supplies don't need to be equal, so you can also run it from +9V and -12V without problem, eliminating the need the the lm7809.

 

[creakndale]

You would need an LM7909 to bring a -12V input to -9V output. An LM7809 is for +9V output.

creakndale