Closed Loop Output Solves the Ledger - Electronic Circuits IX & X: Feedback Control and Sampled Conversion Step by Step

An ideal scalar loop must close every checked value at once.

An ideal scalar loop must satisfy measurement, error, command, and output together. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

All loop values must agree at once

With target 8 volts and forward gain 3, the checked output is 6 volts.

y=6\ \text{V},\quad m=6\ \text{V}

The command equals the ideal output

The measured value is 6 volts, the error is 2 volts, and gain 3 gives command 6 volts.

8+-6=2,\quad 3\cdot 2=6