CH 35 ELECTRIC CIRCUITS

1
CH 35 ELECTRIC CIRCUITS A CIRCUIT IS A COMPLETE
PATH FOR THE ELECTRONS TO FLOW. ELECTRONS FLOW
FROM THE NEGATIVE TERMINAL TO THE POSITIVE
TERMINAL OF A BATTERY. A SWITCH CAN BE USED TO
INTERRUPT THE CIRCUIT.
2

• SERIES CIRCUITS
• ELECTRIC CURRENT HAS ONE PATHWAY.
• TOTAL RESISTANCE IS THE SUM OF THE RESISTORS OR
  R1R2R3 AND SO ON.
• CURRENT IS EQUAL TO VOLTAGE DIVIDED BY THE TOTAL
  RESISTANCE.

3

• 4. VOLTAGE DROP OR POTENTIAL DIFFERENCE DEPENDS
  ON ITS RESISTANCE.
• TOTAL VOLTAGE DIVIDES AMONG THE INDIVIDUAL
  DEVICES IN THE CIRCUIT. SUM OF INDIVIDUAL
  VOLTAGES TOTAL VOLTAGE.
• DISADVANTAGE
• IF ONE PART OF THE CIRCUIT FAILS, THE WHOLE
  CIRCUIT FAILS.

4

• PARALLEL CIRCUITS
• ELECTRICAL DEVICES CONNECTED IN PARALLEL ARE
  CONNECTED TO THE SAME TWO POINTS OF A CIRCUIT.
• THE VOLTAGE IS THE SAME ACROSS ALL DEVICES.
• CURRENT HAS MORE THAN ONE PATHWAY.

5

• TOTAL CURRENT THE SUM OF ALL THE CURRENTS.
• AS THE NUMBER OF BRANCHES IS INCREASED, THE
  OVERALL RESISTANCE IS DECREASED.
• SCHEMATIC DIAGRAMS
• RESISTANCE IS A ZIGZAG LINE.
• BATTERY IS A SHORT AND LONG PARALLEL LINES.
  SHORT LINE IS NEGATIVE.

6
CONNECTING WIRES ARE STRAIGHT LINES. COMBINING
RESISTORS SERIES ADD RESISTORS EX 1? 2 ?
3 ? PARALLEL IT IS HALF THE VALUE OF EITHER
RESISTOR. EX 8 ? 8 ? 4 ? or R1R2 / R1R2
7
LINES THAT CARRY MORE THAN A SAFE AMOUNT OF
CURRENT ARE SAID TO BE OVERLOADED. COULD MELT THE
INSULATION AND START A FIRE. TO PREVENT
OVERLOADING, WE USE BREAKERS OR FUSES. A FUSE
MARKED 20A WILL ALLOW THAT MANY AMPS AND NO MORE.
8
FUSES ARE INSERTED IN A SERIES SO THAT ALL
CURRENT MUST PASS THROUGH THEM.