Johnson DMS, Inc.

Design Hints - If the Volts and Watts are known, find the resistance in ohms, and browse the stock heater table that was sorted by ohms values. Then select some possible sizes to fit the application.

Cutting Watts by Half - The use of a properly rated diode in line would halve the power (watts) when used with AC voltage.

Doubling Voltage - The power is increased four times the original value then the voltage is doubled.

VALUE ASSIGNMENTS
P = Power in Watts
E = Voltage, AC or DC
I = Current in Amperes
R = Resistance in Ohms
Resistors in Series = R_S
Resistors in Parallel = R_P

P=I² R

P=E * I

P=E² / R

I = E / R

I = P / R

I _LINE = I _LEG * 3

E _LINE = E _LEG

P _LEG = P _TOTAL / 3

P _LEG / (E _LINE OR E _LEG) = I _LEG

E _LEG / I _LEG = R _LEG

R = E / I

R = P / I²

R = E² / P

R_S = R₁ + R₂ + R₃

E = I * R

E = P * R

R_P = (R1 * R2) / (R1 + R2)

I _LINE = I _LEG

E _LEG = E _TOTAL / 3

I _LEG = P _LEG / E _LEG

R _LEG = E _LEG / I _LEG