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The store today will thus discussed transistor Uh and how they work.

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An inside look.

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Then we'll talk about basic types and beyond and B and B then we will see basic transistors circuits

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switch and amplifier.

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This is the transistor symbol as you can see here.

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And this is the internal structure of the transistor consists of collector base emitter collector based

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emitter to diodes throw you cannot make a transistor simply by putting two days together back to back.

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It is useful to look at the transistor as made up of diodes to better understand what is happening inside.

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Now let's see this symbol transistor illustration.

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Take a look at this representation of the inner workings of IBM and be transistor Close inspection reveals

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that there are two diodes with their B balls CONNECTED TOGETHER.

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THIS TO BE BORN THE beyond junction is represented by the Nano but black line in an actual transistor.

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The B material would really be just a very narrow strip of material not as represented in this graphic

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but this is for making things easier to understand and this circuit of all sorts is applied between

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the base and diameter.

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As you can see here this is the base and this is diameter.

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The Positive voltage the base is negative to the emitter an additional bar source is applied between

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the collector and the base.

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Then you get the Volt the base.

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That was the Volt the collector the base emitter although it is followed by us which remember of course

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that they ought to conduct electrons allowing the electrons to move left to right and the holes right

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to left

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now.

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Uh as you can see

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something interesting happens in this case through the transistor effect as the electrons from the base

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emit of diode go across the B and junction the B layer is so thin and there are so few holes to accept

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the electrons that allow the electrons continue to flow.

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I and call the base could lift although to start conducting and allowing the current to pass through

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the transistors of the collector in effect a small followed by us on the base emitter diode causes the

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transistor to turn on and bass can throw that emit up to collect all junction so basically you have

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you you can either forward or reverse bias.

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A transistor by controlling its base voltage uh you need to follow by us one of the junction to allow

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it to flow.

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We will see this in more detail once we go next uh in the switch and amplifier circuits.

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This is the same circuit but another verse by a small manner.

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This space is connected to the negative bone as you can see here.

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So I am positive the negative will increase these two areas by selecting areas so no conducting is here

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while the previous example

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while in the previous example as you can see here uh positive and uh positive is connected to this positive

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uh terminal.

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So it's followed by us and positive uh halls.

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We'll go there and they're uh connected uh with electrons so this area will be reduced.

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This answer insulating area and it will conduct RL In the second case the negative and positive born

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negative will attract the positive halls which will make this area wider and will allow electrons to

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pass.

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Now we looked uh that one's a store.

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There are two basic types of funds a solid bending of the arrangement of the material B and B and and

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B and as you can see here as easy phrase to help remember the appropriate symbol is to look at the arrow

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B and B pointing and proudly and B and not pointing in and not be pointing and in B and B pointing and

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proudly so this will help you remember the arrow direction and uh identify the transistor depending

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on that arrow.

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The only operational difference is the source polarity and B I'm not pointing in B and B pointing and

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proudly now if we looked here uh the transistor switch during the next two activities you will build

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a transistor switch and a transistor amplifier.

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They've been out of the 2 and 3 3 9 0 4 transistor as indicated here.

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As you can see uh you must purchase it or you can simulate it using brought us the transistors as a

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switch with the circuit.

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Uh as you can see the circuit uses hook up wire to serve as switches to connect the current to the transistor

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based here.

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What happens when you first apply bar when the base is left floating not connected.

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Now as you can see here we have allowed 300 armed with this total on to the store in the collector to

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limit the current flowing through the lid.

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Remember when the transistor begins to conduct the bathroom the another sort of very raw resistance

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without the current limiting the store too much can will damage the component addition of the 1000 to

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the store and the base Circuit also limits.

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In this case.

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Well the best image updated conducts there is a low resistance path without current limiting the funds

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for can be damaged when the circuit is completed.

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Nothing should happen because the base emits update of the transistor is not biased.

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So the transistor does not conduct.

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Now when we call when the base is connected the nine volt the best metal diode is followed by us and

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conduct.

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This in turn turns on the transistor and current flows through the lid to turn it on.

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You should know that that it goes off when the base voltage is removed.

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Now a full lock.

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Uh.

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Uh.

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And replace the hook up wire connection with connection to our one point five volt battery as.

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What happens when blast one point five volts is applied to the base.

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What happens when the battery is reversed and one point five volt is applied to the base.

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Examine this on your brought aboard or test bench.

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Then get back to this video to see that is on when the voltage is positive on the base.

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The transistor conducts and the lead is the um they are controlling a much larger voltage with a small

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voltage.

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This is the base.

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Uh this is the goal form this circuit to show you that we can control it using a transistor you can

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control a high voltage thing outboard using a small Volt in both and the transistor base.

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Uh this will become more important in the following circuit.

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Uh when a transistor amplifier is explored.

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But for now you cannot.

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You need to understand that we can use small Volt on the base to control high voltage output

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okay.

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Now uh let's see if this circuit the voltage across the variable to stop is the battery voltage at the

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white part of the variable resistor taps of that is stored at different places depending on how the

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screw control on the variable does is to set the battery but this could become a voltage divider sort

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of the voltage on the base can range from ground low voltage to 9 volt and all Volt in between when

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the circuit as well uh you can adjust the range until that it is fully lit using the Volt o meter armies

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of low voltage of the base of the transistor and recall the value on the test pit the voltage was boiling.

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Seven eight Volt.

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So this is the amount of all that is required.

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So the valid can fully it.

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Uh.

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Next you can this crease uh or decrease the voltage by adjusting the variable to the store until that

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it is just barely visible.

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And again measure of the base voltage on that is below the voltage was buoyant.

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Six eight volts.

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Finally move the variable as the store until the lid is fully off.

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And recall the voltage on that is bad.

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The voltage was born six evolve.

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As you can see depending depending on different value of the base voltage uh we can differ on.

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Uh we can examine different behavior of the valid.