one count this signal closes the switch 30 b on resistor 24 a having a resistance rint0 decreasing the total resistance across node b to the resistance of the resistors 24 and 26 a as a result the voltage at node b decreases to vref rint rint0 rext if the voltage on node b is still greater than the voltage on node a the process continues switching in more resistors 26 using switches 30 until the voltage on node b is less than the voltage on node a when this point is reached the process stops and the voltages and digital values on the sw n 0 stay constant unless the value of an internal resistor changes the hysteresis in the comparator 22 prevents the circuit 10 from toggling between two values and offers some noise immunity the digital value sw n 0 then can be distributed to another part of the chip and used to adjust any number of on chip resistors made by the same process such as the resistor 36 if the internal resistor 36 was made by the same process to have the same value as the resistor 24 the same digital values sw n 0 may be used again to set the second internal resistance value using.