c-201 ElEctrical SyStEmS 1 Saca cErtification
Exam with anSwErS 100% corrEct
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)
calculate the time to charge and discharge a capacitor ✔✔ time=RC
R= resistance of circuit
C= capacitance of capacitor in farads
capacitors in power supply ✔✔ Capacitors are used in power supplies to store electrical charge
and to release it when the input voltage drops or when there is a sudden increase in current
demand. This helps to smooth out fluctuations in the input voltage and to provide a steady flow
of current to the load.
inductors in power supply ✔✔ inductors are used in power supplies to store energy in the form
of a magnetic field. When the input voltage fluctuates, the magnetic field in the inductor will
also fluctuate, which can generate a counter-voltage that opposes the changes in the input
voltage. This helps to smooth out the voltage fluctuations and to provide a more stable output
voltage.
Exam with anSwErS 100% corrEct
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)
calculate the time to charge and discharge a capacitor ✔✔ time=RC
R= resistance of circuit
C= capacitance of capacitor in farads
capacitors in power supply ✔✔ Capacitors are used in power supplies to store electrical charge
and to release it when the input voltage drops or when there is a sudden increase in current
demand. This helps to smooth out fluctuations in the input voltage and to provide a steady flow
of current to the load.
inductors in power supply ✔✔ inductors are used in power supplies to store energy in the form
of a magnetic field. When the input voltage fluctuates, the magnetic field in the inductor will
also fluctuate, which can generate a counter-voltage that opposes the changes in the input
voltage. This helps to smooth out the voltage fluctuations and to provide a more stable output
voltage.
