Formulas

Formulas to Memorize:

  • -Circle Area = π r2
  • -Series -Amps = Same
  • -Parallel – Volts = Same
  •                 – 1/Rt = 1/R1 + 1/R2 + etc.
  • -RPM = 120xHz/Poles
  • -1øVD = 2KIL/CM
  • -3øVD = /3KIL/CM
  • -Short-Circuit Amps (SCA) = Amp / %Z/100

ALSO:

  • HP = KW/746

Formula Wheel

Used for circuits of VDC or VAC with Unity Power Factor

4 Quadrants divided into 12 Total

Formula Wheel Memorization Tool

Formula Wheel Memorization Tool
* = 2 EAR PIE
√ = 2 PRPR Ib4E w/’s
÷ = 4 Eiri Peep Irie
x² = 4 PRPR Vertical-Inverted RP’s
See Formula Wheel Memorization Tool below

 

Remember this column: Use 1st Column as a reminder to remember this column: Now remember the Details:
 * = 2 EAR PIE E=I*R & P=I*E
√ = 2 PR PR I = √ P / R

I before E and

I has slants (I, √, /)

E = √ PR
÷ = 4 Eiri Peep Irie E = P ÷ I
I = E ÷ R
R = E ÷ I
I = P ÷ E
x² = 4 PRPR P = R *
R = P ÷
P = ÷ R
R = ÷ P

  • I = E / R
    • Used to find current flowing through each resistor
      • E is VD across each resistor, not voltage source
    • Determines current of each parallel branch
  • I=Es/Rt
    • Es = power supply voltage
    • Rt = Total circuit resistance
  • P = I2R
    • Power as a result of current flowing through a resistance
    • Power can be calculated through P = I2R or Resistance Law of Proportion

Ohms Law Formula Circle

  • Ohms Law is opposition to current flow
  • Relationship between a circuits current intensity (I), electro-motive force (E), and resistance (R)
  • Current flow equals Voltage divided by Resistance
  • Current is inversely proportional to Resistance
    • When Resistance decreases, with Voltage constant, Current increases & vice versa
  • I is directly proportional to E, & inversely proportional to R


PIE Formula Circle

  • Demonstrates relationship between power, current, and voltage