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
- Infix: ((((10 + 2) * 6 + 8) * 6 + 4) * 8 + 4) * 8 + 6
- RPN: 10 2 + 6 * 8 + 6 * 4 + 8 * 4 + 8 * 6 +
- Voltage = 18.0 V
- Output
- 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
CoffeeScript
RPN
<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>
Go
Infix
<lang go>package main
import "fmt"
type Resistor struct {
symbol rune resistance, voltage float64 a, b *Resistor
}
func (r *Resistor) res() float64 {
switch r.symbol { case '+': return r.a.res() + r.b.res() case '*': return 1 / (1/r.a.res() + 1/r.b.res()) default: return r.resistance }
}
func (r *Resistor) setVoltage(voltage float64) {
switch r.symbol { case '+': ra := r.a.res() rb := r.b.res() r.a.setVoltage(ra / (ra + rb) * voltage) r.b.setVoltage(rb / (ra + rb) * voltage) case '*': r.a.setVoltage(voltage) r.b.setVoltage(voltage) } r.voltage = voltage
}
func (r *Resistor) current() float64 {
return r.voltage / r.res()
}
func (r *Resistor) effect() float64 {
return r.current() * r.voltage
}
func (r *Resistor) report(level string) {
fmt.Printf("%8.3f %8.3f %8.3f %8.3f %s%c\n", r.res(), r.voltage, r.current(), r.effect(), level, r.symbol) if r.a != nil { r.a.report(level + "| ") } if r.b != nil { r.b.report(level + "| ") }
}
func (r *Resistor) add(other *Resistor) *Resistor {
return &Resistor{'+', 0, 0, r, other}
}
func (r *Resistor) mul(other *Resistor) *Resistor {
return &Resistor{'*', 0, 0, r, other}
}
func main() {
var r [10]*Resistor resistances := []float64{6, 8, 4, 8, 4, 6, 8, 10, 6, 2} for i := 0; i < 10; i++ { r[i] = &Resistor{'r', resistances[i], 0, nil, nil} } node := r[7].add(r[9]).mul(r[8]).add(r[6]).mul(r[5]).add(r[4]).mul(r[3]).add(r[2]).mul(r[1]).add(r[0]) node.setVoltage(18) fmt.Println(" Ohm Volt Ampere Watt Network tree") node.report("")
}</lang>
RPN
<lang go>package main
import (
"fmt" "strconv" "strings"
)
type Stack []*Resistor
func (s *Stack) push(r *Resistor) {
*s = append(*s, r)
}
func (s *Stack) pop() *Resistor {
le := len(*s) if le == 0 { panic("Attempt to pop from an empty stack") } le-- r := (*s)[le] *s = (*s)[:le] return r
}
type Resistor struct {
symbol rune resistance, voltage float64 a, b *Resistor
}
func (r *Resistor) res() float64 {
switch r.symbol { case '+': return r.a.res() + r.b.res() case '*': return 1 / (1/r.a.res() + 1/r.b.res()) default: return r.resistance }
}
func (r *Resistor) setVoltage(voltage float64) {
switch r.symbol { case '+': ra := r.a.res() rb := r.b.res() r.a.setVoltage(ra / (ra + rb) * voltage) r.b.setVoltage(rb / (ra + rb) * voltage) case '*': r.a.setVoltage(voltage) r.b.setVoltage(voltage) } r.voltage = voltage
}
func (r *Resistor) current() float64 {
return r.voltage / r.res()
}
func (r *Resistor) effect() float64 {
return r.current() * r.voltage
}
func (r *Resistor) report(level string) {
fmt.Printf("%8.3f %8.3f %8.3f %8.3f %s%c\n", r.res(), r.voltage, r.current(), r.effect(), level, r.symbol) if r.a != nil { r.a.report(level + "| ") } if r.b != nil { r.b.report(level + "| ") }
}
func build(rpn string) *Resistor {
st := new(Stack) for _, token := range strings.Fields(rpn) { switch token { case "+": b, a := st.pop(), st.pop() st.push(&Resistor{'+', 0, 0, a, b}) case "*": b, a := st.pop(), st.pop() st.push(&Resistor{'*', 0, 0, a, b}) default: r, _ := strconv.ParseFloat(token, 64) st.push(&Resistor{'r', r, 0, nil, nil}) } } return st.pop()
}
func main() {
node := build("10 2 + 6 * 8 + 6 * 4 + 8 * 4 + 8 * 6 +") node.setVoltage(18) fmt.Println(" Ohm Volt Ampere Watt Network tree") node.report("")
}</lang>
Nim
Infix
<lang python>import strutils,strformat,sugar,sequtils
type Resistor = ref object of RootObj symbol : char resistance,voltage : float a,b : Resistor
proc res(r:Resistor) : float = if r.symbol == '+': return r.a.res + r.b.res if r.symbol == '*': return 1 / (1 / r.a.res + 1 / r.b.res) r.resistance proc setVoltage(r:Resistor, voltage:float) = if r.symbol == '+': let ra = r.a.res let rb = r.b.res r.a.setVoltage ra/(ra+rb) * voltage r.b.setVoltage rb/(ra+rb) * voltage if r.symbol == '*': r.a.setVoltage voltage r.b.setVoltage voltage r.voltage = voltage proc current(r:Resistor) : auto = return r.voltage / r.res proc effect(r:Resistor) : auto = return r.current * r.voltage proc report(r:Resistor,level:string="") = echo fmt"{r.res:8.3f} {r.voltage:8.3f} {r.current:8.3f} {r.effect:8.3f} {level}{r.symbol}" if r.a!=nil: r.a.report level & "| " if r.b!=nil: r.b.report level & "| " proc `+`(r:Resistor,other:Resistor) : auto = return Resistor(symbol:'+', a:r, b:other) proc `*`(r:Resistor,other:Resistor) : auto = return Resistor(symbol:'*', a:r, b:other)
var R1,R2,R3,R4,R5,R6,R7,R8,R9,R10 : Resistor let resistors = [6,8,4,8,4,6,8,10,6,2].map(res => Resistor(symbol:'r',resistance:res.float)) (R1,R2,R3,R4,R5,R6,R7,R8,R9,R10) = resistors let node = ((((R8 + R10) * R9 + R7) * R6 + R5) * R4 + R3) * R2 + R1 node.setVoltage(18) echo(" Ohm Volt Ampere Watt Network tree") node.report()</lang>
Shunting Yard
<lang python>import strutils, sequtils, sugar, strformat
proc shuntRPN(s:string): seq[string] = let ops = "+*" var input = s.replace("("," ( ") input = input.replace(")"," ) ") input = input.replace("+"," + ") input = input.replace("*"," * ") input = input.replace(" "," ") var tokens = input.strip.split tokens = tokens.filter x => x.strip != "" var stack: seq[string] var op: string for token in tokens: case token of "(": stack.add token of ")": while stack.len > 0: op = stack.pop() if op == "(": break result.add op else: if token in ops: while stack.len > 0: op = stack[^1] if not (op in ops): break if ops.find(token) >= ops.find(op): break discard stack.pop() result.add op stack.add token else: result.add token while stack.len > 0: result.add stack.pop()
type Node = ref object kind : string # +=serial *=parallel r=resistor resistance : float voltage : float a : Node b : Node
proc res(node: Node) : float = case node.kind: of "+": node.a.res + node.b.res of "*": 1/(1/node.a.res + 1/node.b.res) else: node.resistance
proc current(node: Node) : float = return node.voltage / node.res proc effect (node: Node) : float = return node.current * node.voltage
proc report(node: Node, level: string = "") = echo fmt"{node.res:8.3f} {node.voltage:8.3f} {node.current:8.3f} {node.effect:8.3f} {level}{node.kind}" if node.kind in "+*": node.a.report level & "| " node.b.report level & "| "
proc setVoltage(node: Node, voltage: float) = node.voltage = voltage if node.kind == "+": let ra = node.a.res let rb = node.b.res node.a.setVoltage ra * voltage/(ra+rb) node.b.setVoltage rb * voltage/(ra+rb) if node.kind == "*": node.a.setVoltage voltage node.b.setVoltage voltage
proc build(tokens : seq[string]) : Node = var stack: seq[Node] for word in tokens: case word: of "+","*": stack.add Node(kind: word, a: stack.pop, b: stack.pop) else: stack.add Node(kind: "r", resistance: parseFloat(word)) stack.pop
proc main = let node = build shuntRPN "((((10+2)*6+8)*6+4)*8+4)*8+6" node.setVoltage 18.0 echo " Ohm Volt Ampere Watt Network tree" node.report
main()</lang>
Perl 6
Infix
<lang perl6>class Resistor {
has Str $.symbol; has Numeric ( $.voltage, $.resistance ); has Resistor ( $.a, $.b );
method res ( ) { given $.symbol { when '+' { return $.a.res + $.b.res } when '*' { return 1 / (1 / $.a.res + 1 / $.b.res) } default { return $.resistance } } }
method set-voltage ( Numeric $voltage ) { given $.symbol { when '+' { my $ra = $.a.res; my $rb = $.b.res; $.a.set-voltage( $ra / ($ra+$rb) * $voltage ); $.b.set-voltage( $rb / ($ra+$rb) * $voltage ); } when '*' { $.a.set-voltage( $voltage ); $.b.set-voltage( $voltage ); } } $!voltage = $voltage; } method current ( ) { return $.voltage / self.res } method effect ( ) { return $.voltage * self.current }
method report ( Int $level = 1 ) { my $pad = '| ' x $level; my $f = ( self.res, $.voltage, self.current, self.effect ).fmt('%8.3f'); say "$f $pad$.symbol"; $.a.report( $level+1 ) if $.a; $.b.report( $level+1 ) if $.b; }
} multi sub infix:<+> (Resistor $a, Resistor $b) { $a.new( symbol => '+', :$a, :$b ) } multi sub infix:<*> (Resistor $a, Resistor $b) { $a.new( symbol => '*', :$a, :$b ) }
my Resistor ($R1, $R2, $R3, $R4, $R5, $R6, $R7, $R8, $R9, $R10) =
map { Resistor.new: symbol => 'r', resistance => $_ }, 6, 8, 4, 8, 4, 6, 8, 10, 6, 2;
my $node = (((($R8 + $R10) * $R9 + $R7) * $R6 + $R5)
* $R4 + $R3) * $R2 + $R1;
$node.set-voltage(18);
say ' Ohm Volt Ampere Watt Network tree'; $node.report;</lang>
Python
RPN
<lang python>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>
Infix
<lang python>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>
zkl
<lang zkl></lang> <lang zkl></lang>
- Output: