(12C) Resistors in Parallel

[Dieter]

(10-25-2018 12:50 PM)Albert Chan Wrote:  Dieter had a better program, with more accuracy by doing R = R1 R2 / (R1 + R2)

Here is how you can do it on the 12C:

Code:

01 ENTER
02 ENTER
03 R↓
04 R↓
05 X<>Y
06 x
07 X<>Y
08 LstX
09 +
10 ÷

As already pointed out, this is all you need for both calculations:

Add up parallel resistors: enter resistor values, one ofter another, and press [R/S]
Simply think of [R/S] as an "add resistor" key.

Find the required resistor for a given total: enter resistors as before, finally enter the desired total and press [CHS] [R/S] [CHS]

Example 1:
Two, three, four or more resistors in parallel.

50 [ENTER] 65 [R/S] => 28,26
120 [R/S] => 22,87
250 [R/S] => 20,96

Example 2:
Find the missing resistor.
Assume you have 100 and 220 Ω, and a total of 50 Ω is required.

100 [ENTER] 220 [R/S] => 68,75
50 [CHS] [R/S] [CHS] => 183,33

Or for Gamo's example:
50 [ENTER] 28,2608 [CHS] [R/S] [CHS] => 65

Dieter