Common Electronic Formula Sheet
Author: Benjamin Luck – Synworks Development Group
Synworks DG Website http://www.synworks.info/
Email: contact@synworks.info
Ohm’s Law
Ohm’s Law calculates the relationship between power, voltage, current, and
resistance.
V = voltage (in volts)
I = current (in amps)
P = power (in watts)
R = resistance (in ohms)
Voltage, in volts (V) V = IR
Current, in amps (I) I = V/R
Power, in watts (P) P = VI
Resistance, in ohms (R) R = V/I
Calculating resistors in series
The formula for calculating resistors in series is pretty simple. Just add up
the resistances.
Rt=R1+R2+R3.
Calculating two resistors in parallel
To calculate two resistors in parallel. Here’s the formula you use:
To calculate three or more resistors in parallel:
Calculating capacitors in parallel
To calculate the value of a string of capacitors in parallel, just add them together:
Ct=C1+C2+C3
Calculating two capacitors in series
Use the following bit of math wizardry when you need to calculate the total
capacitance of two capacitors wired up in series:
Calculating three or more capacitors in series:
Calculating Units of Energy
The watt-hour is one of the most practical units of measure of energy.
Watt-hours = P × T
P stands for power, in watts
T represents time in hours
To calculate watt-seconds, also known as
the joule, divide watt-hours by 3600.
Calculating RC Time Constants
T = RC
T represents time (in seconds)
R stands for resistance (in ohms)
C signifies capacitance (in farads)
Calculating frequency of a signal
Here’s how to calculate the frequency.
Calculating wavelength of a signal
You can use the same basic formula to calculate wavelength if you already
know the frequency of the radio signal:
