**More Specialty Op-Amp Circuits**

**Logarithmic Amplifier**

Vout = K*ln(Vin/Vref)

where K is a scale factor and Vref is a normalization constant (i.e. a constant that will result in a graph area of 1.

Used when logarithmic response is desired, such as sound amplification.

**Antilog Amplifier**

Vout = -Vref*e^^(Vin/╖VT)

where e is Euler's constant, ^^ means "to the poser of", ╖ is

Provides an exponential response (i.e. the opposite to a logarithmic amplifier).

**Simulated Inductor**

When large inductances are required, this circuit can replace bulky inductors.

Responds as if an inductor was in series with the load.

**Capacitance Multiplier**

Simulates a much larger capacitance.

R3 = equivalent circuit resistance

R2 = R3

C2 = simulated capacitance