Chapter 6: Single Phase Rectifiers
A bridge rectifier is connected to the output of a 36-volt transformer. What will be the DC output voltage?
What is: 36x 0.9-2(0.7)=31VDC
What type of three-phase rectifier requires the use of a wye-connected transformer with a center tap?
Half Wave
What is the UJT?
A special device that has two bases and one emitter. It is a digital device because it has only two states: on or off.
How many layers of a semiconductor material are used in the production of an SCR?
4 Layers
When the SCR is connected into an AC circuit, is the output voltage AC or DC (rock on... I'm sorry. I know that joke is probably over used but teehee)
The output voltage is in DC
What is a rectifier?
What is: They are devices that convert alternating or bi-directional current into direct currents.
How many diodes are required to construct a three-phase, full-wave rectifier?
6 Diodes
The UJT is generally classified with a group of devices known as____________. Which includes what 5...items? Pieces?
Thyristors; SCR, Triac, PUT, diac, and UJT
Name the three terminals of an SCR
The Anode, the Cathode, the Gate
After the SCR has been turned on by the gate, what causes the SCR to turn off again?
When the current drops below holding current
What is the simplest type of rectifier?
What is: Two diode full wave rectifier
What type of rectifier has less ripple: a full wave, single-phase rectifier or a half wave, three phase rectifier?
3 phase half wave rectifier
What is a programmable Unijunction Transistor (PUT)?
It is similar to the unijunction transistor discussed previously, EXCEPT that the PUT permits the operating voltage to be set.
How many states of operation does the SCR have?
Two; completely on and completely off.
Explain the operating difference between an SCR and a junction diode
The SCR can be controlled as to when they TURN ON.
What type of single-phase rectifier requires the use of four diodes?
A three-phase, half wave rectifier is connected to a 208 volt, WYE-connected system. What is the average DC voltage produced by the rectifier? (equation)
208 x 1.169(lol, nice) = 243.15VDC
When setting the trigger voltage of a PUT, must the gate voltage be positive or negative with respect to the cathode voltage?
Positive
What is the advantage of the GTO as compared to the SCR
It's ability to control power in a direct current circuit
What is the latest point in the positive half cycle that the SCR can be made to fire?
The latest point is the peak of the wave form; 90 degrees.
An 18- Volt center-tapped transformer is used to construct a two-diode-type rectifier. What will the DC output voltage be?
What is: 9x1.414+12.726v peak
(12.726v x 0.637)-0.7=7.4 VDC
A three phase, full wave rectifier is connected to a 560-volt, delta- connected system. What is the average DC voltage output? (Equation)
560 x 1.35=756 VDC
The connections of a junction transistor are the emitter, base, and collector. What are the connections of a unijunction transistor?
Base 1, Base 2, Gate
The GTO requires from 10-20 times more NEGATIVE gate current to TURN it off than it does to turn on.
By reducing the resistance connected in the gate circuit, is it possible to make the SCR fire earlier than 90 degrees or later than 90 degrees?
By reducing the resistance in the gate you can make the SCR fire earlier.