Technical Resistor Calculator

  • Ohm's Law
  • Series/Parallel
  • Voltage Divider
  • RTD's
  • Wheatstone Bridge
  • RL, RC Filters


Ohm's Law

Enter Any Two Numbers
Press Calculate to find the others.
 
Power (P)Watts
Voltage (V)Volts
Current (I)Amps
Resistance (R)Ohms
       
Ohm's Law
V=IR
Joule's Law
P=VI
Ohm's Law describes the relationships
between Voltage, Current, and Resistance
through a resistor. It is the most
fundamental equation in electronics.
Joule's Law describes the amount of
power that is required to sustain a
certain current through a circuit.

Using these two equations, if we know any two values, we can determine the others.
 

Series/Parallel

Enter Values
Leave One Blank
 
RT
 
R1
R2
R3
R4
 
Find the equivalent resistance (RT)
of resistors in series, parallel, or a combination
Select Circuit Type
Series
Parallel
Triple Series
Triple Parallel
Series - Parallel
Series - Parallel - Parallel
If you get "No Solution"       Result was a Negative Resistance.

Voltage Divider

RT - Total Ohms
Ohms
 
Voltage Dividers
 
Voltage Dividers are very useful for lowering voltages to use as inputs for control circuits. They are nice because the output voltages will track the input voltage very precisly.
 
The output voltages are determined by theratios of the resistors chosen.
 
Use this tab to find the best choice for your application. Fill in empty values, press Calculate.






                Amps
               Volts


               Volts


               Volts


               Volts


               Volts

 
Select Circuit
 
4 Resistors
3 Resistors
2 Resistors

RTD's

Temperature Coefficientof Resistance ( TCR )
 
Certain resistance material undergo a large
change in resistance due to temperature changes.
These changes are controllable and repeatable
making it highly suitable for measuring
temperatures. RTD's are a case of this.
 
TCR is measured in parts per million per C
(ppm/C), i.e. a 1 ohm resistor will change in
value by 0.0045 ohms for every 1C change in
temperature for a 4500ppm/C wire.
 
Use this tab to calculate either the resistance
change or temperature change based on different
standard resistance material.
 
Use the Temperature tab to convert Farenheit to
Centigrade. Temperatures must be in C.
Enter Starting
Conditions
Enter One Ending
Condition
 
Starting Temp ( C ) Ending Temp ( C )
 
Starting Resistance (Ohms) Ending Resistance (Ohms)
 
       
Select TCR
( ppm/C )
 
 +2600: 42% Ni Iron
 +3850: Platinum
 +3900: Copper
 +4500: Balco
 +5000: 99.5% Nickel
 +6000: 99.9% Nickel
Temperature Conversion
Enter Farenheit or Centigrade - click Convert
 Farenheit ( F )Centigrade ( C )


To
  

Wheatstone Bridge

VVolts
 
R1Ohms
R2            Ohms
R3            Ohms
R4            Ohms
 
V0Volts
 
 
VoutVolts











 Standard Circuit
      RTD Circuit

RL, RC Filters

Select Circuit Type
Lowpass RL Circuit
Lowpass RC Circuit
Highpass RL Circuit
Highpass RC Circuit
Enter Any Two Numbers
Press Calculate to find the others.
 
Frequency(F0)Hz
Inductance(L)
mH
Resistance(R)Ohms