Consider the equivalent circuit model of an operational amplifier. The output section consists of a voltage-controlled source in series with the output resistance. In the input section, v1 and v2 denote voltages from the inverting and non-inverting terminals to the ground, respectively. The output voltage of an op amp equals the product of the input voltage difference and the open-loop gain. For small voltage differences, the op amp behaves linearly. If the voltage exceeds the power supply voltage the op amp saturates. The combination of applied voltage and negative feedback ensures that the op amp operates within its linear range. Modern amplifiers have large gains and input resistance, allowing them to be approximated as ideal op amps. An ideal op amp has infinite open-loop gain, infinite input resistance, and zero output resistance. Both input terminal currents and the input offset voltage are zero in an ideal op amp. Additionally, It has infinite bandwidth, allowing it to amplify signals of any frequency, and infinite slew rate, signifying its ability to change the output voltage rapidly over time.