Do Golden rules apply in the following circuits x 2 x sq 1V CK Tse Operational

# Do golden rules apply in the following circuits x 2 x

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+ Do Golden rules apply in the following circuits? + + + + + x 2 x sq. –1V
C.K. Tse: Operational Amplifiers 7 Other examples (where Golden rules work) R 1 R 2 + v i v o Applying the Golden rules, we get This is the non-inverting amplifier . + v i Here, simply This is the voltage follower .
C.K. Tse: Operational Amplifiers 8 Other examples (where Golden rules work) More examples R 2 R f + v 2 v o This is the summing amplifier . + v 2 This is the difference amplifier . R 1 R 3 v 1 v 3 R 1 R 1 v 1 R 2 R 2
C.K. Tse: Operational Amplifiers 9 Other examples (where Golden rules work) More examples R + v i v o This is the integrator. + This is the differentiator (theoretically). In practice, this circuit won’t work!!! v i R C C
C.K. Tse: Operational Amplifiers 10 Examples (where Golden rules do not work) Comparator Since the voltage gain typically exceeds 100,000, the inputs must be within a fraction of a millivolt in order to prevent the output from swinging all the way to extreme positive or negative. It is assumed that the supply voltages are +10 V and –10 V and that the gain is 100,000. 1. If v 1 is larger than v 2 by more than 0.0001 V, the output will swing to +10 V. 2. If v 2 is larger than v 1 by more than 0.0001 V, the output will swing to –10 V. The output cannot make the two inputs equal!!! Golden Rule 1 fails!!!
C.K. Tse: Operational Amplifiers 11 Examples (where Golden rules do not work) Comparator But this simple comparator suffers from a problem if the input signals have noise! The output may switch (jump up and down) when the signals are close to each other. The output cannot make the two inputs equal!!! Golden Rule 1 fails!!!
C.K. Tse: Operational Amplifiers 12 Examples (where Golden rules do not work) Comparator Suppose v 2 = 5V (constant) and v 1 is an input. This circuit is supposed to compare v 1 with 5V. But if v 2 has noise, the outputmay jump when v 2 is near 5V. ± 5V v 1 5V v 2 t v out
C.K. Tse: Operational Amplifiers 13 Examples (where Golden rules do not work) Schmitt Trigger — a better comparator How does it work?

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