BASIC ELECTRONICS - OD1633 - LESSON 1/TASK 2
ET = 40 volts + 60 volts + 100 volts
ET = 200 volts
When you use Ohm's law, the quantities for the
equation must be taken from the same part of the
circuit. In the above example, the voltage across R2
was computed using the current through R2 and the
resistance of R2.
The value of the voltage dropped by a resistor is determined by the applied
voltage and is in proportion to the circuit resistances. The voltage drops
that occur in a series circuit are in direct proportion to the resistances.
This is the result of having the same current flow through each resistor.
The larger the ohmic value of the resistor, the larger the voltage drop
(4) Power in a Series Circuit.
Each of the resistors in a series
circuit consumes power which is dissipated in the form of heat. Since this
power must come from the source, the total power must be equal to the power
consumed by the circuit resistances. In a series circuit, the total power
is equal to the sum of the power dissipated by the individual resistors.
Total power (PT) is equal to:
PT = P1 + P2 + P3 + . . . Pn
Example: A series circuit consists of three resistors having values of 5
Ohms, 10 Ohms, 15 Ohms. Find the total power when 120 volts is applied to
the circuit (figure 25).
R1 = 5 Ohms
R2 = 10 Ohms
R3 = 15 Ohms
E = 120 volts
RT = R1 + R2 + R3