| 摘要 |
<p>Circuit (10) for generating an error voltage (26) which is proportional to the difference between a desired value of a physical parameter and the actual value of the physical parameter. The circuit (10) operates by alternately switching the current from a source (13) through a fixed resistor (11) and a variable resistor (12), the resistance value of which changes as a function of the physical parameter to be controlled. The current is switched between the two resistors so that the average voltage generated across the variable resistor would be equal to the average voltage generated across the fixed resistor if the physical parameter had the desired value. By determining the difference between the average voltage across the resistors, the error voltage (26) can be generated for controlling the physical parameter.</p> |
