An operational amplifier (op-amp) is a circuit component used for signal amplification. An op-amp takes a differential voltage present at its two input terminals, typically labeled V+ and V-, and multiplies the difference (V+ - V-) by a gain factor G; driving out an amplified signal as a single ended output voltage. The op-amp is widely used to boost or amplify input signals to a desired output voltage. Op-amps are effective because of the large amount of gain, or amplification, they can produce. This enables them to be versatile in their implementation in various electronic circuit designs. Op-amps can take on a variety of different behaviors and characteristics primarily from the way they are configured with additional external components such as resistors, capacitors and inductors. An ideal op-amp has infinite open-loop gain, high input impedance and low output impedance. This enables maximum voltage gain, which can prove useful when trying to amplify a very small signal. However, utilizing resistors as negative feedback enables further control of the amount of gain an op-amp exhibits. All the external components that surround the op-amp add to its functionality. The gain, input impedance, output impedance and bandwidth are all determined by the surrounding components of the op-amp. Op-amps are commonly used in nearly all electronics today because of their versatility. They can be used as discrete packaged components on printed circuit boards or as a sub-component in an integrated circuit together with other types of circuits. Multiple op-amps can be used in a cascaded fashion to increase the amount of gain.