Operational Amplifiers Assignment Example | Topics and Well Written Essays - 2500 words

Operational Amplifiers - Assignment Example In case the device is to be used as a gain block, an amplifier that is ideal should have infinite gain. Similarly, the input impedance of the amplifier should also be infinite so as not to draw any power from the driving source. The most commonly used method for analysing stability of an amplifier is the Bode analysis. The basis of measurement here is creation of an open loop magnitude and phase plot to attain the stability for a closed loop. These are also indicators of gain and phase margin. Derivation of the phase margin is done by finding the intersection of the unity gain frequency response of closed loop curve to the open loop response curve (Schmid, 1995). At this frequency the phase will be read from the phase plot. Then the value gotten is subtracted from one hundred and eighty degrees to get the desired phase margin. Gain margin can also be determined in the magnitude plot by the frequency at 180 degrees. Operational amplifiers are linear devices possessing all the qualities that are required to have ideal amplification of direct current. Operational amplifiers are used for filtering or conditioning signal. They can also used to subtract, add, integrate and differentiate mathematical operations. An ideal amplifier consists of three terminals. The negative terminal is the inverting input while the positive terminal is the Non-inverting input. The last terminal is the output port of an operational amplifier. When the same circuit is considered in terms of impedance, R1 = Z1, R2 = Z2. Capacitors and inductors effectively change their impedance dependent upon frequency (ZC = 1/jωC). With capacitors in the circuit as in Figures 1 and 2, ÃŽ ² will be determined by frequency. The gain of the amplifier is constant as the frequency of the signal increases from 1 Hz to around 200Hz. As the frequency of the signal increases beyond the low break frequency i.e. 200Hz the gain increases until it reaches its