4000 Series Logic ICs: The 4051 8-channel analog multiplexer/demultiplexer IC

hey guys welcome back to the 4,000 series series where we're looking at some of the 4,000 series seos chips this one we're looking at is the 4051 it's an analog multiplexer and D multiplexer essentially it's an analog switch it will give you one common output input and also eight uh input and outputs you can use so it's like switching these eight uh input or outputs over to this common one essentially that's what happens so you could use that as an input uh put in analog signal a voltage and then that voltage can be output onto any one of these other outputs here or you can use that as the output and have eight separate inputs that you can switch now I've rigged up a little circuit just to demonstrate um the common I/O so I'm using that as an output and these separate ones as an input we're using some voltage dividers so I'm just using some resistor voltage dividers here I've got them all detailed down here but we'll go through that as as I show you the circuit it also has a binary truth table on these select pins here so you put them high or low and it dictates which one of the outputs or inputs is going to be used in this case we're using them as inputs so we've got our circuit here I've put an LED onto the common output so that we can see a visual difference but I've also hooked it up to a multimeter so that you can see a change in the voltage now be aware that this um the the current drawer on this led is going to pull the voltage down slightly from what we might expect using the general calculation for figuring out a voltage divider so on Y2 that's the common uh input output just on pin 15 we've connected that directly to VCC on y4 we have which is pin 1 we've got a resistor divider with two 470 ohm resistors and I expect that to roughly half the voltage so it's going to give us 2.6 volts uh and on y5 which is pin five on the left hand side we've got a 2K resistor in resistor 2 and 470 in resistor 1 so that's hopefully going to give us about 4.3 volts now I've put the calculation down here so you can see it but it's a general uh calculation that you can use and on our select pins I've put some buttons so that we can ping out this truth table and select the ones that we want to see so if I just turn the power on and I know we've got one on Y 2 and it goes zero it goes 1 2 4 so if I press uh the second one it should get us the highest voltage and again I said that the voltage would drop if I just pull out that um LED it should shoot up to 5.2 but I'll pop it back in there so that just you have visual representation uh in pin one we have nothing in pin two we've got our uh VCC and in pin four that's y4 we've got this 2.6 volts and if I pull out the LED it won't drop too much cuz it's not drawing a lot of current but it will go up to 2.6 so that's what I expect to see and you'll see that the LED is very dim there and on y5 which is pin one and sorry select zero and select two so these ones here we've got 3.3 volts but it actually should be 4.3 so let's pull out that there we go 4.3 volts so it's very easy to use this this chip to select various inputs and outputs so we could feed voltage into this common pin and get those voltages out on the other pins but I'm just using it as an input uh an output at the moment so the 4051 can expand the number of analog inputs that you have on your microcontroller but it can also expand the number of analog outputs now generally with an Arduino you're limited by the range of the ADC but this is a true analog device so we'll just kick out voltages that you put into the into the inputs

Channel: David Watts

Views: 27,564

Keywords: 4000 series, 4051, analog, arduino

Id: YHOmru_t_-k

Length: 4min 6sec (246 seconds)

Published: Sun Jan 10 2016