Basic Electronic Formula

Ohm’s Law

Ohm’s Law defines the relationships between power (P), voltage (V), current (I) and resistance (R).

Formula #1

Voltage – is the difference in electrical potential between two point in a circuit.

V = IR

V = voltage (measured in volts)

I = Current ( measured in amperes)

R = Resistance (measured in ohms)

Formula #2

Resistance – determines hoe much current will flow through a component.

R = V/I

V = voltage (measured in volts)

I = Current ( measured in amperes)

R = Resistance (measured in ohms)

R(serial) = R1 +R2 +Rx

P(parallel) = R1R2/(R1+R2)

Formula #3

Current – is the intensity of electrical flows on a  conductor; like a pressure of the water through the pipe leading to a faucet.

I = V/R

V = voltage (measured in volts)

I = Current ( measured in amperes)

R = Resistance (measured in ohms)

Formula #4

Power – is the amount of current times the voltage level at a given point measured in wattage or watts.

P = VI

V = voltage (measured in volts)

I = Current ( measured in amperes)

P = Power(measured in watts)

Can rearrange as  P = VV/ R  or  P = IIR

Formula #5

Voltage Divider

Vo/Vs = R2/(R1+R2)

Vo = Voltage output

Vs = Voltage supply

R1 = 1st resistor

R2 = 2nd resistor

Formula #6

Reactance – is the alternative current (AC) equivalent of resistance

Reactance of capacitor

f = frequency (measured in Hz)

C = capacitance (measured in uf)

Pye = 3.142

Reactance of inductor

f = frequency (measured in Hertz, Hz)

L = inductance (measured in Henry, H)

Pye = 3.142