Rectifiers and Battery Chargers: Part A Flashcards
Rms stands for?
Root mean square
Average dc value is equal to what?
Instantaneous value at any time
One cylce is represented as how many °
360°
Period (t) is a time measured over?
One complete cycle. 360°
Period foumula
T= 1/f
Frequency formula
F = 1/T
Peak value is known as
Maximum value
Peak to peak value if a sine wave is voltage or current?
Both
Peak to peak is always how much
Twice the peak voltage
Veff formula
Vmax/root2
Effective value is also known as
Rms value
Vrms formula?
Vmax/root2
Voltmeters read what type of voltage
Effective/rms
Averge value of a sine wave taken over a complete cycle is always ?
Zero because + / - values
Meter set to dc on a pure ac source will read
Zero
Double subscript notation is used when
Polarity of one point in a cct with respect to second point
What does a dc meter measure
Average
Touch lead together of a ohm meter reads
Zero
Olm meter OL means
Open cct
Ammeter has a resistance of
Zero
Oscilloscope measure
Harmonics, ground fault test current abd instrumentation signals
Transducer on oscilloscope
Converts the measured quantity into a voltagw signal and displays a graph
If two scope leads each have a reference lead, should both reference leads be connected go the cct or isolated
One isolated
Valence electrons the most outershell
Valence shell
Conductors have high or low resistance?
Vety low resistance
Good conductors have how many valence electrons?
One two or three cause little energy is required for dislodge the electrons from the atom
Electrons that loosely bound to the atom are called
Free electrons. Cause little resistance
Like copper gold silver aluminum
Elements that have 5-8 valence electrons behave as?
Insulators
Semiconductors as insulators
Neither good or bad insulators
Semi condutors have how many valene electrons
4
What material is most commonly used in a semi conductor?
Silicon
But germanium is also used
Electronic devices made from semi conductor are known as
Solid state devices
Colalent bonds has how many valence electrons?
Each atom shares itd four valence electrons with the adjoining stoms causing material to act as a if each atom had 8 electrons in the outer shell
Voltage is applied to ptype material the tendecy is for electrons too
Shift into holes closer to the positive terminal and leaving behind new holes
Photoconductive cells are known as
Light dependent resistors LDR
When energy is applied to semi conductor material what happens to electrons
Break their covalent bond
What is photoconduction?
Property that exhibits lower resistance when exposed to light energy
PN junction
P type and n type material formed side by side in the same semi conductor
Diode behaves as a
Switch
Arrow head points towards
Away from anode and towards the cathode
Barrier voltage of germanium?
0.3v
Barrier voltage of silicon
0.7v
A diode that will not allow current to flow if the anode is negative with respect to the cathode is called
Reverse bias
Ideal reverse diode resistance is
Infinity
Characteristic curve vertical and horizontal
Vertical is current
Horizontal is voltage
Voltages above safe maximum that cause diode to break down are called
Breakdown voltage and avalance voltage
Diode current ratings?
Low
Medium
High
Medium current diodes are?
Stud mounted or press fit
Stud mounted with a pigtail diodes are typically in what Amp range
150a to 500a
Type of large current carrying diode
Hockey puk
VRRM
Repetitive reverse maxium
Reverse voltage rating can be listed as
Vrrm
Vpr
How to check a diode
Multimeter or component tester
3 common diodes
Freewheeling
Directional
Rectifier
Freewheeling diode is used,m
Control the destructive effect of the cemf ehen the switch is opened in a dc cct
Freewheeling diode is also known as
Suppression or
Protection
Other names for directional diodes?
Blocking
Steering
Isolating
Diodes and batteries
Diodes prevent tje battery with the highest voltage from acting like a power source and discharging into other batteries
Fire alarm bells use what type of diode
Blocking diodes
Led stands for
Light emitting diode
Rectifter changes what
Ac to dc
Two types of doped semi conductive materials
P type
N type
When light shines on a LDR what happens to the resistance
Decreases
Open switch reads how much v
Source voltage
Open switch reads how much current
Zero
Closed switch reads how much vols
Zero
Closed switch reads how much current
It will read how ever many amps
Why is effective voltage used in ac
Effective heat
What is frequently
Cycles per second
Vp formula
Vrms/0.707
Ntype has what charge
Neutral but behaves negative
Ptype charge is
Neutral but behaves postive
What is a simple and practical method of showing correct battery connection polarity?
Use a light emitting diode