#### What does this calculator do?

This calculator was created to accompany our new book on SPICE simulation of guitar amplifier circuits.^{1}
At one point in writing a large-signal triode model,
a curve fit is required using quadratic regression.
As a convenience for readers of the book, this calculator performs these calculations automatically.
Specifically, the calculator computes optimal values of K1, K2, and K3 for the formula

A = K1(V_{G})^{2} + K2(V_{G}) + K3

The algorithm requires at least 3 data points and handles up to 9 data points.
Leave unused inputs equal to "0".

#### References

^{1}Richard Kuehnel,

**Guitar Amplifier Electronics: Circuit Simulation**, (Seattle: Amp Books, 2019).