C-202 (Electrical Engineering) SACA
CERTIFICATION FOR ELECTRICAL SYSTEMS 1
QUESTIONS AND ANSWERS (100% Correct
and Accurate
total load on an AC circuit with inductors
known: XL = 2πfL
1. Total inductive reactance (XL) = XL1 + XL2 + XL3 + ... (for series connection)
1 / Total inductive reactance (XL) = 1 / XL1 + 1 / XL2 + 1 / XL3 + ... (for parallel
connection)
2. Total load = supply voltage / (1 / total inductive reactance + 1 / total
resistance)
Define capacitance
Charge stored per unit potential difference
three types of capacitors
electrolytic, ceramic, and film.
how to safely discharge a capacitor
1. disconnect power
2. use DMM on voltage first
3. If the voltage is less than a few volts, the capacitor is considered discharged
and can be handled safely.
4. switch to resistance if still charged
5. to discharge the capacitor slowly. To do this, connect one end of the resistor
to one of the terminals of the capacitor, and the other end of the resistor to the
other terminal of the capacitor.
, how to test a capacitor with a DMM
Once the DMM is connected to the capacitor, you should switch the DMM to
the capacitance measurement mode, and take a reading. The reading should
be displayed on the DMM's display, and should be within the specified
tolerance range for the capacitor. If the reading is outside of the tolerance
range, the capacitor may be defective and should be replaced.
effect of a capacitor in a DC circuit
In a DC circuit, a capacitor acts as an open circuit when charged, meaning
that it does not allow current to flow through it. When the capacitor is fully
charged, no current will flow through it. However, when the capacitor is
discharged, it acts as a short circuit, allowing current to flow freely.
effects of a capacitor in an AC system
allowing alternating current (AC) to pass through it. This is because a
capacitor's impedance (resistance to AC) increases with frequency, so at low
frequencies it acts as a short circuit and allows current to pass through easily,
but at high frequencies its impedance increases and it acts as an open circuit,
blocking the flow of current.
calculate total capacitance
add capacitances
calculate total capacitive reactance
X_C = 1 / (2 pi f * C)
X_c= capacitive reactance in ohms
f= frequency in hertz
c= capacitance in farads
calculate total load on an AC circuit with capacitors
X_C = 1 / (2 pi f * C)
CERTIFICATION FOR ELECTRICAL SYSTEMS 1
QUESTIONS AND ANSWERS (100% Correct
and Accurate
total load on an AC circuit with inductors
known: XL = 2πfL
1. Total inductive reactance (XL) = XL1 + XL2 + XL3 + ... (for series connection)
1 / Total inductive reactance (XL) = 1 / XL1 + 1 / XL2 + 1 / XL3 + ... (for parallel
connection)
2. Total load = supply voltage / (1 / total inductive reactance + 1 / total
resistance)
Define capacitance
Charge stored per unit potential difference
three types of capacitors
electrolytic, ceramic, and film.
how to safely discharge a capacitor
1. disconnect power
2. use DMM on voltage first
3. If the voltage is less than a few volts, the capacitor is considered discharged
and can be handled safely.
4. switch to resistance if still charged
5. to discharge the capacitor slowly. To do this, connect one end of the resistor
to one of the terminals of the capacitor, and the other end of the resistor to the
other terminal of the capacitor.
, how to test a capacitor with a DMM
Once the DMM is connected to the capacitor, you should switch the DMM to
the capacitance measurement mode, and take a reading. The reading should
be displayed on the DMM's display, and should be within the specified
tolerance range for the capacitor. If the reading is outside of the tolerance
range, the capacitor may be defective and should be replaced.
effect of a capacitor in a DC circuit
In a DC circuit, a capacitor acts as an open circuit when charged, meaning
that it does not allow current to flow through it. When the capacitor is fully
charged, no current will flow through it. However, when the capacitor is
discharged, it acts as a short circuit, allowing current to flow freely.
effects of a capacitor in an AC system
allowing alternating current (AC) to pass through it. This is because a
capacitor's impedance (resistance to AC) increases with frequency, so at low
frequencies it acts as a short circuit and allows current to pass through easily,
but at high frequencies its impedance increases and it acts as an open circuit,
blocking the flow of current.
calculate total capacitance
add capacitances
calculate total capacitive reactance
X_C = 1 / (2 pi f * C)
X_c= capacitive reactance in ohms
f= frequency in hertz
c= capacitance in farads
calculate total load on an AC circuit with capacitors
X_C = 1 / (2 pi f * C)
