Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
38 Cards in this Set
- Front
- Back
|
Power supplies convert_________. |
AC power to DC power |
|
|
Power supplies have___ sections. |
5. Input >>> Rectifier>>> Filter>>> Regulator>>> Protection. |
|
|
The input section_____________. |
Steps up or down the AC voltage. |
|
|
The Rectifier section changes ____________. |
Changes AC to pulsating DC. |
|
|
The filter section changes_________. |
Pulsating DC into smooth DC. |
|
|
The Regulator section___________. |
Maintains the output DC at a constant level. |
|
|
Diode rectifiers convert________. |
AC power to pulsating DC power. |
|
|
Half wave rectifiers have one diode and use_____ of the input signal. |
Half. |
|
|
Full wave rectifiers have two diodes and use______ of the input signal. |
All. |
|
|
Bridge wave rectifiers have four diodes and use_______ of the input signal. |
All. |
|
|
In a Half Wave Rectifier, the output frequency of the ripple is______ as the input frequency. |
The same. |
|
|
In a Full Wave Rectifier, the output frequency of the ripple is________the input frequency. |
Twice. |
|
|
Checking for normal operation of a Rectifier circuit requires comparing calculated____________ with measured_________. |
Output voltage Output voltage. |
|
|
Zener Diodes are used as voltage regulators and operate in the break down voltage area otherwise called__________. |
Vz |
|
|
Zener Diodes act like a junction diode when______ biased and________ biased below Vz. |
Forward Reverse |
|
|
Checking a Zener diode with an analog ohmeter will show_____ ohms at forward bias, and______ ohms at reverse bias below Vz. |
Low @ forward bias High @ reverse bias below Vz |
|
|
The purpose of a power supply is to_________________. |
Convert AC power to DC power. |
|
|
Which circuit in a power supply is optional? |
Protection. |
|
|
The purpose of a series voltage Regulator is to maintain a constant output___________________. |
Voltage to a load. |
|
|
In a parallel voltage Regulator, what causes Eout to increase? |
DC input voltage increases or the load current decreases. |
|
|
A Zener diode is reverse biased when_______________. |
The anode is more negative than the cathode. |
|
|
What component is usually found faulty in a voltage Regulator circuit? |
The Zener diode. |
|
|
What is the advantage of an IC Regulator over a multicomponent Regulator. |
Internal thermal protection. |
|
|
What is the max current output for the 7812 IC Regulator. |
1.5 Amps |
|
|
What is the purpose of a uni junction transistor? |
To switch voltage. |
|
|
A UJT turns on when___________. |
Input voltage exceeds a specified level. |
|
|
A UJT is "on" when____________. |
Base one to emitter current flows. |
|
|
What happens to an SCR when it is turned on and gate current is removed? |
The SCR remains on. |
|
|
The purpose of a UJT oscillator is to_________. |
Change DC power to AC power. |
|
|
The operation of a basic UJT oscillator is based on______. |
RC time constant. |
|
|
An SCR is turned off by________. |
Stopping or reducing anode current. |
|
|
The average voltage applied to a load when the input voltage has a RMS value of 25 volts and the SCR has a conduction angle of 30 degrees is______. |
2.1 VoltsDC |
|
|
The most common fault in a SCR circuit______. |
Is the SCR. |
|
|
Relays can have__________. |
One or more poles. |
|
|
The first step in checking a relay is to_______. |
Check inputs. |
|
|
In which step of the four step troubleshooting procedure are circuit measurements taken? |
Step 3. |
|
|
Once the gain (output) has been calculated, the recommended OP-AMP troubleshooting step is to________. |
Measure the output of the amplifier. |
|
|
Operational amplifiers use what three amplifier circuits? |
Differential, common collector, and push-pull. |
