Chapter 3: Ohm's Law

• He discovered the Ohm’s Law

  Georg Simon Ohm
• It is used to determine the amount of electric power in the circuit.

  Ohm’s Law
• True or false: Ohm’s law applies to both DC and AC circuits.

  True
• It is the amount of current through a one-ohm resistance that has one volt of potential difference applied across it.

  One ampere
• It is the potential difference across a one-ohm resistance that has one ampere of current through i

  One volt
• It is the amount of opposition in a resistance that has a V/I ratio of 1, allowing one ampere of current with one volt applied.

  One ohm
• The formula which states that V and I are directly proportional for any value of R.

  Ohm’s Law
• In ohm’s law, increases of volts will __________ the current.

  Increase
• It shows how much current the resistor allows for different voltages.

  Volt-ampere characteristic graph
• In a volt-ampere characteristic graph, the value in y axis or ordinate is _______________.

  Current values
• In a volt-ampere characteristic graph, the value in x axis or abscissa is _____________.

  Voltage values
• In ohm’s law, voltage and current are __________.

  Directly proportional
• This type has a nonlinear volt-ampere characteristic

  Nonlinear resistance
• Whether the resistor is linear is not, the current is ________ for more resistance, with applied voltage constant.

  Less
• It equals the work done in one second by one volt of potential difference in moving one coulomb of charge.

  One watt of power
• It is the time rate of doing work.

  Power
• It is the time rate at which charges is forced to move by voltage.

  Electric power
• 1 horse power is equal to____________

  764 Watts or 550 ft lb/s
• One horse power is approximately equal to ____________.


  ¾ kW
• It is the power used during a period of time.

  Work
• It is a sudden involuntary contraction of the muscles, with a feeling of pain, caused by current through the body. It can be fatal

  Shock
• The greatest shock hazard is from ______ that can supply appreciable amounts of power.

  High-voltage circuits
• The value of “let go” current for men

  9mA
• The value of “let go” current for women.

  6mA
• The greatest danger of shock is form a source having an output of ________ with enough power to maintain the load current through the body when it is connected across the applied voltage.

  More than 30 V
• A piece of equipment known as a power supply can provide a

  variable dc output voltage to electronic circuits under test.
• A red-colored jack provides connection to the positive (+) side of the dc voltage whereas a black-colored jack provides connection to the negative (-) side.
• volt-ampere characteristic of R shows how much current the resistor allows for different voltages
• When the voltage, V, is constant, the relationship between I and R is not linear.
• If you hold a conducting wire in each hand, the resistance of the body across the conductors is about 10,000 to 50,000 ohms.