(HP-97) Design one-shot multivibrators

[SlideRule]

Designing or analyzing timing circuits that use the popular 74123 one-shot multivibrator (Fig. 1) will be much quicker on a programmable calculator. The program shown in Fig. 2 will run on either an HP-67 or HP-97 calculator. However you can easily program other calculators to solve a basic timing equation, with which you can closely approximate a one-shot's timing curve
T = 0.32 (R ÷ 0.7)C + 11.8 R0.837 where
T is the pulse duration (nS),
R is the resistance (kΩ)
C is the capacitance (pF),
as in Fig. 1. [attachment=7276]
1. A one-shot multivibrator, based on the 74123 IC
has three basic parameters. If you know two of them
you can calculate the third from an equation that
approximate the timing curve.

Given any two or the three parameters, you can calculate the third. The equation is accurate for all values of C. The calculator program employs a recursive method with three iterations to solve for resistance.
To use the program first enter known parameter, then its user-defined key. Then depress the key set aside for the unknown parameter. If any of the components are outside recommended limits, an error signal will be displayed.

Fig. 2
001*LBL E <>nS
002 STO E
003 F3?
004 RTN
005 GSB 2
006 RCL C
007 ×
008 GSB 1
009 +
010 STO E
011 SCI
012 DSP 1
013 RND
014 FIX
015 DSP 0
016 RTN
017*LBL 1
018 RCL D
019 .
020 8
021 3
022 7
023 Y^X
024 1
025 1
026 .
027 8
028 ×
029 RTN
030*LBL 2
031 .
032 7
033 RCL D <>kΩ
034 +
035 .
036 3
037 2
038 ×
039 RTN
040*LBL C
041 ENT↑
042 FRC
043 X=0?
044 GTO C
045 CLX
046 EEX
047 6
048 ×
049 ENT↑
050*LBL C <>pF
051 R↓
052 STO C
053 F3?
054 RTN
055 RCL E
056 GSB 1
057 -
058 GSB 2
059 ÷
060 STO C
061 .
062 9
063 X⇄Y
064 X≤Y?
065 GTO e
066 FIX
067 DSP 0
068 RTN
069*LBL D
070 STO D
071 F3?
072 GTO D
073 3
074 STO I
075 1
076 0
077 STO D
078*LBLd
079 GSB 2
080 RCL C
081 ×
082 GSB 1
083 +
084 RCL E
085 X⇄Y
086 ÷
087 RCL D
088 ×
089 STO D
090 DSZ I
091 GTO d
092*LBL D
093 4
094 .
095 9
096 X⇄y
097 X≤Y?
098 GTO e
099 5
100 0
101 X⇄Y
102 X>Y?
103 GTO e
104 DSP 1
105 RTN

Historical significance?

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Source: 400 Ideas for Design (Calculator/Computer Circuits & Software)

listing corrected, thanks mfleming.