Okay, on this slide here, what I wanted to do is introduce the transformer. They're up to this point let's let's go back to the previous slide. And what we've done is we've put a generator in there so I thought maybe we would put a transformer because that's primarily what what is done for the for the most part. And this this, this actually would go into my hundred and 20 volts AC source. Alrighty, and everything's the same. It's transformer coupling, I would get a sine wave between if you remember this is my primary winding The transformer and this here is my secondary winding.

Alright, we went over that in a in a previous in a previous video. And basically a if we have a turns ratio here. All right, depending on what the turns ratio, what we get on the primary will be something different than what's on the secondary. But let's say I've got a one to one winding on the so what's on my, my primary will will end up in my secondary. That's pretty much it. Everything else I said on the previous slide about the decay and the RC time constant is hold is true.

It's just that instead of showing you this little brown little dot with up with a sine wave in there a little round circle All the sine wave in there. Basically, we've got a transformer and that's how we create my AC voltage or transfer my AC voltage. All right. Again, when I go in, I do that design module on power supplies. We'll go into how to pick the transformer and so forth. All right, we've, we've got a lot in this module here.

So I just don't want to convolute it with other stuff. That's all. So here's my primary winding my secondary winding, this is a transformer and an upset here. All right, talk to you soon. See on the next slide. Okay, now we're looking at a full wave rectifier, okay.

And if you'll notice, we have conduction on each Each one of these cycles here, all right, and we've actually added another diode right there. All right. So let me go through this and see how it works. We've got a transformer here. And I've got 120 volts AC on my primary. Remember, this is my primary, I'll just abbreviate it pri, and over here is my secondary.

Alright, but notice, I've got a tap on my transformer right here and it's going to ground it's called a center tap. So I have a center tap right there. Okay, and I'm tapping in the middle of the transformer. And from the center, tap to the top winding here. It's 12 volts AC and from the center, tap to the bottom winding here. It's 12 volts AC and what do I have across?

The whole winding? 24 volts? AC. Alright, so we're only using half of the winding are we? Okay? All right.

So let's, let's see how this works and how we get that waveform. So let me stop, clear the slide off. All right. Now one of the things that I didn't mention before, and I'm going to mention it now there's, there's 180 degree phase shift and a transformer. So if I look at my wave form on my sine wave on my primary side, when this goes plus, that wave form is the opposite. So when this goes plus up here, that wave form goes minus.

All right, it's still a sinusoidal waveform. Okay? It's just that the depending on the turns ratio, the transformer, the voltages is going to change somewhere. But the only thing is when I go plus here, I go negative here. And if I go negative here, I go plus there, that's all. Alright.

So let me clear those off. All right. So now, let's say I go minus here that means I go plus here. So plus, minus, plus on the other winding minus, all right. So which diode will conduct this one? Right?

This one, let me put a zero reference. So on this one here, D one can ducks All right? So let's see how it goes. Okay, negative here minus and plus against the arrowhead. So now I'm going to say D one here. All right, stop.

I'm going to clear the slide off. Now when this portion of the transformer goes positive, this goes negative, minus n plus, minus and plus, which diode conducts. D two. So let's see how that goes. Sound Now, we have d two on my positive and then I have D two over here. So I have D one, D two, D one again, but b one, D two, D one and D two and so forth.

All right. So, these diodes because the configuration of both of those diodes and the way my transformer action works allows my current flow through my load in only one direction. Even though back here in the primary I have a reversal of current direction because of those diodes in my secondary I allow current through the diode, sorry, current flow through the resistor in only one direction. And that, again is determined by the the configuration of D one and D two. All right. If you don't understand it, rewind it go back again.

Alright, it's not that difficult maybe the first time you look at it, it does let me stop clear the slide off I just remember the polarities plus and minus, then plus and minus and then minus and plus, minus and plus. All right, another way that you can think of that is when my anode is at the positive portion of my transformer, this Dyer will conduct and when my anode of D one is that is in the positive excursion up here. The one will conduct and that's why I get the D one. I'm sorry, that's why I get the D two D one D two and so forth. So, these diodes alternate conduction from my primary input, all right, okay. Okay, so now what is the average value?

All right, well, the average value is is still the xec voltage seen by a volt meter. So if I put a volt meter here, it would read this, again the average value equals 0637. So, the average value DC equals zero dot 637 times the peak voltage. But in the case of a full wave rectifier it's zero dots. 67 times the peak value. And the peak value is 12 volts times 1.414, which gives me 17 volts.

And when I do my math, I get 10.89 volts. Notice we don't divide by two because there's 100% of conduction because we added this other diode. So basically we've increased our average Jeff DC value just by adding another diode and actually, we're using both both excursions of my sine wave up here and down there and that that's why Okay, we kind of flipped that bottom on over with the extra diet. enforce current through this resistor in the same direction. That's it. That's my full.

That's my full wave rectifier. Again, that's how it works with a diode. We're going to be doing a module or a video lesson on power supplies and we'll pick the components and go into it a little bit better. We've got transistors to do in this module. So again, we need to still we laying foundation. Okay, Nuff said.

Let's go to the next slide. Okay, now we are looking at a full wave rectifier. All right, and Nope, she put it onto there. So this is a full wave bridge, I'm sorry. bridge rectifier and notice we've Got a total of four diodes right there, here, here, here and here. And we don't have any center tap.

All right. So basically the bridge rectifier, we use the whole winding of the transformer. Alright. What is that going to do for us? Well, if we go back to the previous slide, notice, ah, we had 12 volts AC, half of the winding, so the whole winding would have been 24. All right.

But guess what's going to happen if I use the whole winding? What's my average DC value going to be? It's going to go up, isn't it? So let's go back. And let's look at this. So what we've done here is is he's I took this from another book that I had instead of writing it, and he likes he likes whole flow the way he showed it.

I like this diagram the way he took the diodes out and so forth. But I, you know that I use electron flow. So I'm going to kind of go the opposite way, the value across my load, which is right here, which is showing you right here, the value across my load. I'm sorry, the current flow through my load is going to be the same. So let's look at this. This is plus and minus, I'm going to get electron flow through the diode.

This is going to be plus i mean this is going to be minus, this is going to be plus up through the diode and down. Alright, so now we are conducting on the positive, turn the positive portions of my sine wave right there. All right. And then This is what happens when I repeated I get it here and here. Okay, now my polarity changes. And now I'm going to flow this way.

Minus and plus. All right. And now I'm I'm what I'm actually doing is conducting on the negative half, but because of the diode or the configurations of the diode, I kind of flip this up. So now what I get is, this will fill in here. All right, and I get a full wave and not a full wave. I get I get conduction on every cycle of my sine wave.

This is called pulsating DC. If I haven't said it before I think I did. That's called pulsating DC. And then I put a capacitor in there. And I can smooth it out just like I showed you before. i.

So, basically, the criteria is very similar to a full wave rectifier only. I'm using what they call a bridge circuit. This is a bridge circuit. I'm using all the diodes and I'm using the full voltage on the secondary of the transformer. All right, I'm gonna stop here, clear off the slide. We'll just look at the the average DC value on this and then this section is closed.

Okay. Okay, again, here's my diode rectification full wave bridge. I we've talked about it I use the whole secondary winding, all the voltage on my whole winding Okay, my average value is 2.637 times peak. Okay, I have 24 volts AC. All right, I do my math, here's my peak voltage, the average value would be point 637 times 34 volts. So if I put a meter across here and I measured it, I would read 21.16 volts DC right there.

That's what I would read. All right, um, this ends it. This ends this portion of diodes and rectifiers. And we spoke about diodes and semiconductors and turn on voltage and reverse bias and so forth. I hope you enjoyed it. The next section will be on transistors in this course this module and we'll see you over there.