Ideal Vs Practical or Real Opamp

Posted By on September 12, 2014


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Series voltage regulator
Practical OP-AMP

Characteristics Ideal Op Amp Real Op Amp
 Voltage Gain An ideal op amp will have infinite voltage gain.. A real op amp can only produce a finite gain.
 input impedance An ideal op amp will have infintely high input  impedance. A real op amp has finite input impedance.
Output Impedance An ideal op amp will have zero output impedance. A real op amp will always have some output impedance, though it is low. A typical value can be
75Ω.
Frequency In an ideal op amp, the gain that the op amp produces will be independent of frequency. In real op amps, the gain that is produced is only for a certain bandwidth of frequencies.
Input Voltage Offset In an ideal op amp, if no voltage is applied to the inverting and noninverting input pins, the op amp will output a voltage of 0, since there is no difference at all of the voltage applied to the 2 input pins. A real op amp will have slight offset even if the voltage applied to the pins are the same. To correct this offset, voltage must be applied to the offset pin.
 Voltage Swings to Supply Rails In an ideal op amp, the ac voltage which is fed into the op amp to be amplified will swing all the way up for the DC positive supply rail and all the way down for the DC negative supply rail, making 100% efficient use of the DC voltage supplied to an op amp. In real op amps, the amplified signal will not fully reach the DC supply rails. They will fall short of it.
Output swings
In an ideal op amp, the output will swing instantly to the amplified voltage value. There will be no time delay between the time the voltage is input into the op amp till the time it is output. It will all be instantaneous. In real op amps, the amplified signal will take time to reach the fully amplified voltage value. This is determined by the slew rate of the op amp.
Series voltage regulator
Practical OP-AMP

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Posted by Akash Kurup

Founder and C.E.O, World4Engineers Educationist and Entrepreneur by passion. Orator and blogger by hobby

Website: http://world4engineers.com