Practical takeaway
Electrical power tells you how quickly electrical energy is being used or delivered. In radio work, watts matter everywhere from power supplies to transmitters.
Electricity & Electronics
Electrical Power
Connect watts, volts and amps with the same visual memory trick.
TECHNICIAN FOUNDATION4 of 16
Technician exam focus
Be able to use P = E × I, E = P ÷ I and I = P ÷ E. When the answer uses division, P is the numerator.
The P-E-I triangle
PEI
The equations are P = E × I, E = P ÷ I, and I = P ÷ E. If you like the triangle, use it. If not, remember the pattern: whenever the answer uses division, P is on top.
P = E × I
Power in watts equals voltage times current.
E = P ÷ I
Voltage equals power divided by current.
I = P ÷ E
Current equals power divided by voltage.
STEMulation
Change the power relationship
Try familiar radio numbers: 13.8 volts and 20 amps. Then change one value and watch the watts respond.
Applied next step
Power ratios in decibels
See how +3 dB, −3 dB, +10 dB and other gain/loss values change power in a radio signal chain.