Click here to purchase the entire book in PDF format. Open Loop Voltage Gain Usually, we use op amps with a feedback loop. This is in order to control what we said in the last chapter was the op amp's infinite gain. In fact, an op amps does not have an infinite gain - but it's pretty high. The gain of the op amp when no feedback look is connected is somewhere up around 100 dB. Of course, this is also dependent on the load that the output is driving, the smaller the load, the smaller the output and therefore the smaller the gain of the entire device. The open loop voltage gain is a meaurement of the gain of the op amp driving a specified load when there's no feedback loop in place (hence the ``open loop''). 100 dB is a typical value for this specification. It's value doesn't change much with changes in temperature (unlike some other specifications) but it does vary with frequency. As you go up in frequency, the gain of the op amp decreases.