Series-Parallel Resistor Adding and Standard Resistance Values

Description

Origin: HP-34C Student Engineering Applications, August 1979, p. 15

This program will add series and parallel resistors, providing full use of the stack for intermediate answers. It also calculates the closest standard 5%, 10% or 20% resistor values.
The resistor adding and standard value routines are completely independent and either can be loaded and used without the other. The resistor adding routine is line 001-007 and the standard values routine is line 008-093.
The resistor adding routine (line 001-007) can also be loaded and run with the Ohm's Law program.
Note that capacitors in parallel and series can be substituted for resistors in series and parallel, respectively.

Instructions:
  1. To find standard resistance values go to step 6.
  2. Key in resistor value. Press ENTER.
  3. Key in next resistor value.
  4. To add parallel press B, for series press +
  5. To add other resistors go to step 2, 3 or 4. For standard resistance values go to step 6.
  6. Enter tolerance (5, 10, or 20 only). This only needs to be done the first time, or whenever a change is desired. Press GSB 1.
  7. Enter non-standard resistor size and calculate nearest standard value. Press A.
  8. For more calculations go to step 2, 3, 6 or 7.

Example 1:



Determine resistance from A to B

680 ENTER 120 B
330 + 680 + 220 B
680 ENTER 470 B
+ → 461.5767 (RAB, ohms)

Example 2:
Find the nearest 10% standard value resistor that will replace the circuit in Example 1, assuming results from Example 1 still remain in the display.
10 GSB 1 A → 470.0000 (R, ohms)

Program Resources

Labels

Name Description Name Description
 A  6
 B Add parallel resistance  7
 0  8
 1 Tolerance for standard resistance value  9
 3

Storage Registers

Name Description
 2 Step size
 3 Normal R
 4 Exp of R
 5 This step
 6 Temp
 7 Temp

Program

Line Display Key Sequence Line Display Key Sequence Line Display Key Sequence
000 032 42,21, 0 f LBL 0 064 43 44 g INT
001 42,21,12 f LBL B 033 45 3 RCL 3 065 44 6 STO 6
002 15 1/x 034 45 5 RCL 5 066 2 2
003 34 x↔y 035 43,30, 7 g TEST x>y 067 6 6
004 15 1/x 036 22 9 GTO 9 068 43,30, 7 g TEST x>y
005 40 + 037 45 2 RCL 2 069 22 6 GTO 6
006 15 1/x 038 20 × 070 4 4
007 43 32 g RTN 039 44 5 STO 5 071 7 7
008 42,21, 1 f LBL 1 040 22 0 GTO 0 072 45 6 RCL 6
009 1 1 041 42,21, 9 f LBL 9 073 43,30, 7 g TEST x>y
010 2 2 042 32 8 GSB 8 074 22 3 GTO 3
011 0 0 043 44 7 STO 7 075 1 1
012 10 ÷ 044 45 5 RCL 5 076 40 +
013 13 10ˣ 045 45 2 RCL 2 077 43 32 g RTN
014 44 2 STO 2 046 10 ÷ 078 42,21, 3 f LBL 3
015 33 R⬇ 047 32 8 GSB 8 079 8 8
016 43 32 g RTN 048 44 6 STO 6 080 3 3
017 42,21,11 f LBL A 049 45 7 RCL 7 081 45 6 RCL 6
018 43 13 g LOG 050 20 × 082 43,30, 6 g TEST x≠y
019 36 ENTER 051 11 √x̅ 083 43 32 g RTN
020 43 44 g INT 052 45 3 RCL 3 084 8 8
021 44 4 STO 4 053 43 10 g x≤y 085 2 2
022 30 054 32 7 GSB 7 086 43 32 g RTN
023 1 1 055 45 7 RCL 7 087 42,21, 7 f LBL 7
024 40 + 056 45 4 RCL 4 088 45 6 RCL 6
025 13 10ˣ 057 13 10ˣ 089 44 7 STO 7
026 44 3 STO 3 058 20 × 090 43 32 g RTN
027 1 1 059 43 32 g RTN 091 42,21, 6 f LBL 6
028 44,30, 4 STO 4 060 42,21, 8 f LBL 8 092 45 6 RCL 6
029 1 1 061 48 . 093 43 32 g RTN
030 0 0 062 5 5
031 44 5 STO 5 063 40 +