Imágenes de páginas
PDF
EPUB
[ocr errors][merged small]

183. Parallel Circuits

Figure 60 is an example of a simple parallel circuit, with two resistors connected in parallel across a generator. As indicated by the arrows, the current from the generator separates into two parts, each resistor receiving a part of the total current. The larger fraction of current flows through the branch of less resistance, and the smaller fraction of current flows through the branch of greater resistance. The two parts of the current join again upon leaving the resistors.

a. The total current (I,) in a parallel circuit is the sum of the currents in the separate branches:

I1 = 11 + 12 +13 +........

b. The voltage (E) across each branch of a parallel circuit is the same:

[merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors]
[blocks in formation]
[blocks in formation]

The following example illustrates the method of using Ohm's law and the principles of series circuits (par. 182) to solve series dc circuits.

Example:

Solve the following problem:

Resistors R1, R2, and R, are connected in series across a
110-volt generator (fig. 62). If resistor R1 = 6.5 ohms,
resistor R, 10.3 ohms, and resistor R2 = 7.6 ohms, what
2 =
is the total current in the circuit? What is the voltage drop
across each resistance?

[blocks in formation]

ng example illustrates the method of using Ohms' law and the principles of 】 183) to solve parallel de circuits.

Example:

Solve the following problem:

In figure 63, a resistor of 200 ohms (R1), a resistor of 600 ohms (R), and an unknown resistor (R3) are connected in parallel across a source of emf. The voltage across R, is 40 volts. The current through the resistor of unknown value (R) is 0.40 ampere. Find (a) the value of R3, (b) the total

[blocks in formation]

Circuits

one unknown.

circuit, with series-connected resistors R, and R connected in paralcombination connected in series with resistors R, and R., is shown

D figure 64. to illustrate the method of

Example: Find the current through each resistance and the voltage drop across each resistance in A, figure 64.

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][subsumed][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]
« AnteriorContinuar »