# Unity Gain

Discussion in 'General Electronics Discussion' started by piedon, Jun 13, 2013.

1. ### piedon

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Jun 13, 2013
Hello Folks, just trying to get an understanding of what unity in electronics is and would like your opinion on how I understand it.

From what I understand, unity come into play with ocillators and amplifiers. If unity is 1, there isn't any increase or decrease of the output signal. If unity is greater than 1, the output will increase in amplitude, if the untiy is less than one, then the output will begin to dampen and decrease.

Does unity corolate to the impedance between components?

Thank you for the help.

2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,497
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Jan 21, 2010
Unity can mean several things

For example, you may have unity voltage gain (i.e. the voltage out is the same as the voltage in), but your output allows a greater current. This is known as a buffer and can allow a high impedance signal to drive low impedance inputs. It also provides a gain in power.

The gain doesn't correlate with impedance of components. The input and outpu currents do to a greater extent though.

Also note that a negative gain has meaning. A gain of -1 is a unity gain, but where the output is inverted with respect to the input. This is a 180 degree phase shift.

Other phase shifts can also occur but it is complex to describe them. In this case "complex" means you need to use complex numbers.

3. ### davennModerator

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Sep 5, 2009
or you can have unity gain across a range of frequencies
that takes some electronics effort as usually when left uncontrolled, gain will vary greatly with frequency

Dave