Digital Electronics: Logic Gates - Integrated Circuits Part 1

In this experiment we will see

integrated

circuits

and we will build some experiments from the course notes and implement them on our boards. First we'll look at the chips themselves. This is the type of chip. which we're going to use the type that's packaging, we're going to use is a dip and chip package, which means plastic jewel line and pin package and the pins are three tenths of an inch a

part

and you can see that your little circle here at the top it indicates that it's pin one, so there's a little notch at the top of that chip and there's a circle.

Darrington indicates that this pin here is pin one so we know how to identify it. with you, be very careful that we order the dip pack, dip pack chips and we are working on our experiments, not knowing when you are doing your projects later and other types of packaging are available. This is an SOS e which is a small plane it's too big a circuit and you can see it's a considerably smaller scale the inside of the chip could be exactly the same and it could do exactly the same function so just the packaging plastic on the pin lands and so on is what's different about this. format again, it has a circle to indicate pin one, but you can see that it is considerably smaller than the dip package chip served.

It is possible that the chip that we don't want to use is only available in a dip package and in which case we can use a board like this, it is a converter board that allows us to basically, we can use these type of legs to convert it into a thread that allows us allow us to connect it to our breadboard and both. sides of the board, you see this design, this sign is point eight, the point pitch on the other side is 0.6 and there at point six, this is a six millimeter point, so you can see that we have aligned the line. chip against the channels and push the starter today on the

part

icular pins and then we will be able to use these pins here in a more accessible way on our board.

It is possible that certain types of chips that we need to use are only available in SOI c form and that means in dip format which means we would have to use a converter board like this okay so we are going to use the dip format to our dip packaging for our experiments, so each chip has an identification number and here we can see that this is the mm7 for added security. 0h n all the letters mean something, the AMM in this case refers to the manufacturer which is Fairchild Semiconductor, it could also be letters like SN which would refer to Texas Instruments for example the 7/4 is the way you know .

I guess this is the gist of what you did in terms of finding the number that makes sense on your chip at 7/4 and you skipped the the letters between seven four zero eight refer to the particular type of chip, this is a 2 input quad and one gate, so there are four to enter

gates

on this particular chip, the end at the end refers to the type of packaging, so we know that this is a type of dip package, so the N is refers to different headings of the inline dual package and finally we have the HC t in the middle which refers to the particular

logic

family that the chip belongs to, in this particular case it is a high speed CMOS with TTL.

logic

levels so that this is the particular type of chip that we are going to use for our experiments, the first thing we need to do is connect power to the chip, so I configured the rails so that we have easy access and this chip pin holder in particular it has to be connected to ground and pin 14 has to be connected to VCC, so here we are going to connect pin 14 to VCC and pin seven to ground management is the part that I have.

I'm not connected to the supply, yes, percent, the chip is part and now we have found our input on pins one, two and three again. We can tell you our first pin by the circle that is visible there at the top of the chip that we have. one to our inputs and pin three as our output so we need some way to see our output so we're going to use an LED for this so I'm just going to use one LED on the pin tree connect the LED well this is a piece of cable. I'm going to bring the LED here and I'm just going to use a little resistor connected to ground that's before and then we'll just tie that back together.

Remember that on the longer leg the positive is connected to the pin tree and the shorter leg. is connected to ground, which is just to ground, it triggers a small resistance, so now we have our circuit and we can test it and we can say, well, let's connect both inputs so that they are high and in this particular case, when we can, let's turn on the power . You should see very quickly that our LED should illuminate pins one and two, okay, both to grab, yes, both. Sorry, reserve VCC at five volts when we turn on our power supply.

Now you will see the LED turn on. I'm just going to leave the power supply ready. I go to unplug one of my inputs and ground it and there's a scene. If now that it is connected to ground, the LED is off, if I do it the same way with the other pins, it will have the same effect, you know from the light, the truth table for a NAND gate, that both inputs have to be high for the LE, okay, again set up Bowden, it sets me high, so we can light or LED like this, now what we're going to do is we're going to say, well, moving these wires is a little awkward, so let's connect two switches , so I'm just going to turn off the power and connect two switches, so I'm going to use these push button switches and just make sure you have them in the right orientation and let's connect them.

I'm going to connect the first one so that it touches the pin, it has the same function as pin 1, that means I'm on you. We're going to have to connect to the other side of the switch, just make sure they do a tricky move, they might come out and I'm going to place the other switch and right next to it, okay, so we have two switches, don't press them. okay on the boards and these buttons are going to provide my inputs and we should see that when our circuit works, my circuit is connected and we get a high level, only the LED lights we can have a high level only when both buttons are pressed at the same time. so we need to connect to say well, let's say well, let's connect the back to this to this side of this pin, make sure you go to the right thanks to the other side, let's connect our enters on the other side of your switch. let's connect that to the second input and the second switch is already connected to pin 1 and we just need to connect the other side to our fire, she was going to go up, she should reach it.

Now we turn on your circuit, you will see something unusual. This happens it doesn't work and if we press the buttons and get it right the LED almost always stays on so it has no effect but you should see the LED flashing on and off as you go so see that it doesn't It's very stable now. The reason for this is because I'll let you think for a minute what the reason for this is. Why is it unstable? Why does it seem to flash between on and off while I press the buttons even though there is no input?

Make sure the moment is off, think about that.