# Understanding basic electrical math for troubleshooting series and parallel circuits

**Amps = I** (Intensity) (Current)

**I = E/R**- The current (Amps)(Intensity) is equal at each load in a series circuit
**To find the Amps in a series circuit:**Combine the total resistance for each load in series (TTL_R = R_a + R_b + R_c ....), divide applied voltage by total resistance (I=E/TTL_R), and current is equal (same) at every load.

- The current (Amps)(Intensity) varies (I=E/R) for each load in a parallel circuit

**Volts = E** (Electromotive Force)

**E = I * R**- Voltage across a parallel circuit is equal to each load
- Voltage through a series drops at each load
**To find Voltage drop through a series circuit:**- Total R (resistance) of series circuitÂ Â | TTL_R = R_a + R_b + R_c
- Divide V (volts) by total R (resistance) | I = V - TTL_R
- Left with I (current)
- Apply I (current) to every R (resistance) per load | V_a = I * R_a, V_b = I * R_b, â€¦
- At each load Voltage Drop = R (resistance) * I (current)
**The sum of the voltage drop is always equal to the amount of applied voltage**

Color on diagram below depicts voltage weakening and not a comparison of voltage drops.

**Ohms = R** (Resistance)

**R = E / I**- Sum of resistance (3 circuits in example) in parallel is = 1/( (1/X) + (1/Y) +(1/Z) )
- Sum of resistance (3 circuits in example) in series is = X + Y + Z

**Watts = w** (Power)

**W = I * E**