Solid State Devices I
description
Transcript of Solid State Devices I
![Page 1: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/1.jpg)
Solid State Devices I
Benchmark Companies Inc
PO Box 473768
Aurora CO 80047
![Page 2: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/2.jpg)
Transformers
Back
Objectives:• Definition of Transformer• Uses of a Transformer
•Step-Up•Step-Down•Isolator
![Page 3: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/3.jpg)
Transformers
Back
![Page 4: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/4.jpg)
Transformers
Back
Primary Secondary
NP NS
:
:
Symbol
A transformer typically has two separate windings with a Varying number of turns (N). They are the primary winding And Secondary winding
![Page 5: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/5.jpg)
Transformers
Back
The two lines in the center of the two coils indicate this Transformer has a core. (No lines indicates no core)
Primary Secondary:
NP NS:
Symbol
![Page 6: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/6.jpg)
Transformers
Back
There is another type of transformer called a center-tap transformer (photo). It has many uses in today’s electronics
Primary Secondary:
NP NS:
Symbol
![Page 7: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/7.jpg)
Transformers
Back
The benefit of center-tap transformers is the availability of several voltage levels on the secondary winding.
Primary Secondary:
NP NS:
Symbol
![Page 8: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/8.jpg)
Transformers
BackVirtually every electronic devices which uses AC has to convert the power to a usable level.
![Page 9: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/9.jpg)
Transformers
Back
Primary Secondary:
Symbol
A transformer is a typically a pair of coils where ones magnetic field acts on the other
![Page 10: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/10.jpg)
Transformers
Back
Primary Secondary:
Symbol
The flow of current through the primary causes current to flow in the opposite direction in the secondary.
![Page 11: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/11.jpg)
Transformers
Back
Primary Secondary:
Symbol
The direction of current is designated by dots on either end of the windings.
![Page 12: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/12.jpg)
Transformers
Back
RECALL current flows through the primary winding, a magnetic field is produced that causes a current to flow through the secondary winding.
Primary Secondary:
Symbol
NP NS:
![Page 13: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/13.jpg)
Transformers
Back
The current flowing through the primary winding causes the current to flow in an opposite direction through the secondary.
Primary Secondary:
Symbol
NP NS:
![Page 14: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/14.jpg)
Transformers
Back
The current direction is indicated by the dots on each coil. Having the dot on the same end tells us the output is in phase.
Primary Secondary:
Symbol
NP NS:
![Page 15: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/15.jpg)
Transformers
Back
Output Voltage is directly proportional to the number ofTurns in the secondary winding (Ns) with respect to the Primary windings(Np). This is called the Turns Ratio.
Primary Secondary:
Symbol
NP NS:
![Page 16: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/16.jpg)
Transformers
Back
The relationship is defined as follows:
Ep/Es = Np/Ns
Primary Secondary:
Symbol
NP NS:
![Page 17: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/17.jpg)
Transformers
Back
Example: Primary winding has 20 turns and the Secondary Winding has 40 turns. The result is the input voltage is Increased by a factor of 2 . 10/V(out) = 20/40 >> 400/20 = V(out) = 20 volts. This is a Step-up Transformer
NP NS:
![Page 18: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/18.jpg)
Transformers
Back
Likewise, if a Primary winding has 40 turns and the Secondary Winding has 20 turns. The result is the input voltage is decreased by ½. 10/V(out) = 40/20 >> 200/40 = V(out) = 5 volts. This is a Step-down Transformer
NP NS:
![Page 19: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/19.jpg)
Transformers
Back
Sometimes, there is a need to isolate voltage source from the Circuit. This can be done by using a transformer with a 1:1 Turns ratio
NP NS:
![Page 20: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/20.jpg)
Transformers
Back
NP NS:
You should understand that there is no net power lossIn an ideal transformer. That means that: Power (primary) = Power (secondary)
Ip*Ep = Is*Es
![Page 21: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/21.jpg)
Transformers
Back
NP NS:
Moving Ip and Is to one side of the equal sign and Ep and Es to the other yields:
Ip/Is = Es/Ep (Inversely Proportional)
Current (in) Current (out)
Voltage (in)Voltage (out)
![Page 22: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/22.jpg)
Transformers
Back
NP NS:
Transformers and the secondary circuit have a loading Effect on the source voltage that is proportional to the Turns ratio
Np/Ns x R1 = RL
![Page 23: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/23.jpg)
Transformers
Back
Example: Primary winding has 20 turns and the Secondary Winding has 40 turns. If R1 = 10KOhms the Load Resistance (RL) = (20/40)x10k = 5kOhms. Note the difference in expected current needed to drive the circuit.
NP NS:
![Page 24: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/24.jpg)
Transformers
Back
Summary on TransformersFormulas:
Vin/Vout = Np/Ns
Iin/Iout = Ns/Np
Pin = Pout
Np/Ns x R1 = RL
The Formulas above of are based on the assumption thatThe transformer is ideal and no power loss occurs in the
Transformer.
![Page 25: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/25.jpg)
TransformersSummary
Back
Transformers take a waveform and scale the waveform according to the turns ratio of the primary coil with respect to the secondary coil. If the turns ratio is greater than 1 the waveform is increased, if the ratio is less than one, the waveform is decreased.
Sine waveinput
Scaled WaveformTransformer
![Page 26: Solid State Devices I](https://reader036.fdocuments.us/reader036/viewer/2022081418/568143c3550346895db04fe0/html5/thumbnails/26.jpg)
End of Presentation
Back