Resistance calculator

Introduction

• Calculate the resistance of a network of resistors.
• The resistors can be connected in series or parallel.
• Use infix or RPN to state the network.
• Calculate resistance, voltage, current and power for every resistor and operation.

Background

• Serial Resistors: the sum of the resistors gives the equivalent resistor
• Parallel Resistors: the inverse of the sum of the inverse of the resistors
• The voltage drops over the resistors
• Current = Resistance / Voltage
• Power = Current * Voltage

Input

Parallel Resistor Calculator

• Infix: ((((R8 + R10) * R9 + R7) * R6 + R5) * R4 + R3) * R2 + R1
• RPN: 10 2 + 6 * 8 + 6 * 4 + 8 * 4 + 8 * 6 +

Output

• Voltage = 18.0 V
• 10.000 ohms in the upper left corner is the equivalent resistance.
• The first operation is 10 + 2 = 12 which can be found in the three middle rows.

    Ohm     Volt   Ampere     Watt  Network tree
 10.000   18.000    1.800   32.400  +
  4.000    7.200    1.800   12.960  | *
  8.000    7.200    0.900    6.480  | | +
  4.000    3.600    0.900    3.240  | | | *
  8.000    3.600    0.450    1.620  | | | | +
  4.000    1.800    0.450    0.810  | | | | | *
 12.000    1.800    0.150    0.270  | | | | | | +
  4.000    0.600    0.150    0.090  | | | | | | | *
 12.000    0.600    0.050    0.030  | | | | | | | | +
 10.000    0.500    0.050    0.025  | | | | | | | | | r
  2.000    0.100    0.050    0.005  | | | | | | | | | r
  6.000    0.600    0.100    0.060  | | | | | | | | r
  8.000    1.200    0.150    0.180  | | | | | | | r
  6.000    1.800    0.300    0.540  | | | | | | r
  4.000    1.800    0.450    0.810  | | | | | r
  8.000    3.600    0.450    1.620  | | | | r
  4.000    3.600    0.900    3.240  | | | r
  8.000    7.200    0.900    6.480  | | r
  6.000   10.800    1.800   19.440  | r

Python

<lang python>

1. RPN

class Resistor : def __init__(self, resistance, a=None, b=None, symbol='r'): self.resistance = resistance self.a = a self.b = b self.symbol = symbol def res(self) : return self.resistance def setVoltage(self, voltage): self.voltage = voltage def current(self) : return self.voltage / self.res() def effect(self) : return self.current() * self.voltage def report(self,level=""): print(f"{self.res():8.3f} {self.voltage:8.3f} {self.current():8.3f} {self.effect():8.3f} {level}{self.symbol}") if self.a: self.a.report(level + "| ") if self.b: self.b.report(level + "| ")

class Serial(Resistor) : def __init__(self, a, b) : super().__init__(0, b, a, '+') def res(self) : return self.a.res() + self.b.res() def setVoltage(self, voltage) : ra = self.a.res() rb = self.b.res() self.a.setVoltage(ra/(ra+rb) * voltage) self.b.setVoltage(rb/(ra+rb) * voltage) self.voltage = voltage

class Parallel(Resistor) : def __init__(self,a,b) : super().__init__(0, b, a, '*') def res(self) : return 1 / (1 / self.a.res() + 1 / self.b.res()) def setVoltage(self, voltage) : self.a.setVoltage(voltage) self.b.setVoltage(voltage) self.voltage = voltage

def build(s) : stack = [] for word in s.split(' '): if word == "+": stack.append(Serial(stack.pop(), stack.pop())) elif word == "*": stack.append(Parallel(stack.pop(), stack.pop())) else: stack.append(Resistor(float(word))) return stack.pop()

node = build("10 2 + 6 * 8 + 6 * 4 + 8 * 4 + 8 * 6 +") print(" Ohm Volt Ampere Watt Network tree") node.setVoltage(18.0) node.report() </lang>

Python

<lang python>

1. Infix

class Resistor : def __init__(self, resistance, a=None, b=None, symbol='r') : self.resistance = resistance self.a = a self.b = b self.symbol = symbol def res(self) : return self.resistance def setVoltage(self, voltage) : self.voltage = voltage def current(self) : return self.voltage / self.res() def effect(self) : return self.current() * self.voltage def report(self,level="") : print(f"{self.res():8.3f} {self.voltage:8.3f} {self.current():8.3f} {self.effect():8.3f} {level}{self.symbol}") if self.a: self.a.report(level + "| ") if self.b: self.b.report(level + "| ") def __add__(self,other) : return Serial(self,other) def __mul__(self,other) : return Parallel(self,other)

class Serial(Resistor) : def __init__(self, a, b) : super().__init__(0, a, b, '+') def res(self) : return self.a.res() + self.b.res() def setVoltage(self, voltage) : ra = self.a.res() rb = self.b.res() self.a.setVoltage(ra/(ra+rb) * voltage) self.b.setVoltage(rb/(ra+rb) * voltage) self.voltage = voltage

class Parallel(Resistor) : def __init__(self,a,b) : super().__init__(0, a, b, '*') def res(self) : return 1 / (1 / self.a.res() + 1 / self.b.res()) def setVoltage(self, voltage): self.a.setVoltage(voltage) self.b.setVoltage(voltage) self.voltage = voltage

[R1,R2,R3,R4,R5,R6,R7,R8,R9,R10] = [Resistor(res) for res in [6,8,4,8,4,6,8,10,6,2]] node = ((((R8+R10) * R9 + R7) * R6 + R5) * R4 + R3) * R2 + R1 node.setVoltage(18) print(" Ohm Volt Ampere Watt Network tree") node.report() </lang>

CoffeeScript

<lang coffeescript> nd = (num) -> num.toFixed(3).padStart 8

class Resistor constructor : (@resistance,@a=null,@b=null,@symbol='r') -> res : -> @resistance setVoltage : (@voltage) -> current : -> @voltage / @res() effect : -> @current() * @voltage report : (level) -> print "#{nd @res()} #{nd @voltage} #{nd @current()} #{nd @effect()} #{level}#{@symbol}" if @a then @a.report level + "| " if @b then @b.report level + "| "

class Serial extends Resistor constructor : (a,b) -> super 0,a,b,'+' res : -> @a.res() + @b.res() setVoltage : (@voltage) -> ra = @a.res() rb = @b.res() @a.setVoltage ra/(ra+rb) * @voltage @b.setVoltage rb/(ra+rb) * @voltage

class Parallel extends Resistor constructor : (a,b) -> super 0,a,b,'*' res : -> 1 / (1 / @a.res() + 1 / @b.res()) setVoltage : (@voltage) -> @a.setVoltage @voltage @b.setVoltage @voltage

build = (s) -> stack = [] for word in s.split ' ' if word == '+' then stack.push new Serial stack.pop(), stack.pop() else if word == '*' then stack.push new Parallel stack.pop(), stack.pop() else stack.push new Resistor parseFloat word stack.pop()

node = build "10 2 + 6 * 8 + 6 * 4 + 8 * 4 + 8 * 6 +" node.setVoltage 18.0 print " Ohm Volt Ampere Watt Network tree" node.report "" </lang>