WEBVTT 1 00:00:00.080 --> 00:00:03.210 In this lesson, we're going to talk about power supply units, 2 00:00:03.210 --> 00:00:05.520 also known as PSUs. 3 00:00:05.520 --> 00:00:06.480 Now, every computer 4 00:00:06.480 --> 00:00:09.240 is going to have some sort of power supply unit. 5 00:00:09.240 --> 00:00:10.650 This is because power supplies 6 00:00:10.650 --> 00:00:13.350 are going to give all the computer systems and components 7 00:00:13.350 --> 00:00:15.930 the direct current they need to be able to operate. 8 00:00:15.930 --> 00:00:17.220 Now in all of our homes, 9 00:00:17.220 --> 00:00:19.320 when you plug something into the wall outlet, 10 00:00:19.320 --> 00:00:20.520 you're actually getting voltage 11 00:00:20.520 --> 00:00:23.580 in what's known as AC or alternating current. 12 00:00:23.580 --> 00:00:27.600 In America, this is 110 volts to 120 volts AC. 13 00:00:27.600 --> 00:00:29.070 And over in Europe and Asia, 14 00:00:29.070 --> 00:00:33.540 you're usually going to see this as around 230 to 240 volts AC. 15 00:00:33.540 --> 00:00:36.330 But our computers need a much lower voltage 16 00:00:36.330 --> 00:00:39.030 and they need a direct current voltage. 17 00:00:39.030 --> 00:00:40.620 Alternating current actually cycles 18 00:00:40.620 --> 00:00:43.230 between positives and negatives repeatedly. 19 00:00:43.230 --> 00:00:46.440 For instance, in the United States we use 60 Hertz power, 20 00:00:46.440 --> 00:00:48.450 which means 60 times per second, 21 00:00:48.450 --> 00:00:52.560 our voltage is going from 120 positive to 120 negative 22 00:00:52.560 --> 00:00:53.910 and back again. 23 00:00:53.910 --> 00:00:57.420 So, our computers have to take that cycling voltage 24 00:00:57.420 --> 00:00:59.340 and turn it into something they can understand 25 00:00:59.340 --> 00:01:01.140 which is a direct current, 26 00:01:01.140 --> 00:01:04.230 which means it's always going to be at a certain voltage. 27 00:01:04.230 --> 00:01:06.390 For example, if you have a double-A battery, 28 00:01:06.390 --> 00:01:09.000 that's 1.5 volts DC. 29 00:01:09.000 --> 00:01:10.710 That means on one end of the battery, 30 00:01:10.710 --> 00:01:14.100 there is always going to be a positive 1.5 volts. 31 00:01:14.100 --> 00:01:16.410 And as you move from one side of the battery to the other 32 00:01:16.410 --> 00:01:17.880 as you're going through the circuit, 33 00:01:17.880 --> 00:01:19.440 you're going to keep that direct current 34 00:01:19.440 --> 00:01:24.420 or that flow of voltage at 1.5 volts the entire time. 35 00:01:24.420 --> 00:01:26.430 So when you think about a power supply, 36 00:01:26.430 --> 00:01:28.290 remember its main purpose 37 00:01:28.290 --> 00:01:31.920 is to deliver direct current or DC low voltage power 38 00:01:31.920 --> 00:01:34.620 to all the different components inside of your PC 39 00:01:34.620 --> 00:01:37.650 when it receives an alternating current or AC power 40 00:01:37.650 --> 00:01:39.180 from your wall outlet. 41 00:01:39.180 --> 00:01:40.770 Now when you look at a power supply, 42 00:01:40.770 --> 00:01:43.800 they tend to be a fairly large size unit. 43 00:01:43.800 --> 00:01:46.800 Even in smaller and less powerful office computers, 44 00:01:46.800 --> 00:01:47.700 your power supply 45 00:01:47.700 --> 00:01:49.980 is going to be about the size of your fist. 46 00:01:49.980 --> 00:01:52.200 Whereas when you start using gaming PCs 47 00:01:52.200 --> 00:01:55.080 or more powerful workstations that require more power, 48 00:01:55.080 --> 00:01:57.090 you're going to have a larger power supply unit 49 00:01:57.090 --> 00:02:00.720 that is two, three, or four times as large as that. 50 00:02:00.720 --> 00:02:02.430 Now inside this power supply unit, 51 00:02:02.430 --> 00:02:05.580 it needs to do the conversion from AC to DC. 52 00:02:05.580 --> 00:02:07.800 And to do that, it's going to use a transformer 53 00:02:07.800 --> 00:02:10.290 and a series of regulators and filters. 54 00:02:10.290 --> 00:02:13.320 The transformer is going to do the large power drop for us, 55 00:02:13.320 --> 00:02:17.280 going from that 110 or 120 volt AC inside the US 56 00:02:17.280 --> 00:02:21.810 or that 230 or 240 volts AC over in Europe and Asia 57 00:02:21.810 --> 00:02:25.620 into voltages that are at current at 12 volts or less. 58 00:02:25.620 --> 00:02:28.650 Once the transformer part gets it down to a lower voltage, 59 00:02:28.650 --> 00:02:30.810 it will then pass through filters and regulators 60 00:02:30.810 --> 00:02:32.490 to get to the right levels of DC 61 00:02:32.490 --> 00:02:34.860 that are needed by your various components. 62 00:02:34.860 --> 00:02:37.680 So remember when it comes to your computer, 63 00:02:37.680 --> 00:02:40.380 it needs good clean power from the outlet 64 00:02:40.380 --> 00:02:41.910 to the computer's power supply. 65 00:02:41.910 --> 00:02:44.610 And then that power supply is going to convert that AC 66 00:02:44.610 --> 00:02:46.290 or alternating current input 67 00:02:46.290 --> 00:02:48.780 into a DC or direct current output 68 00:02:48.780 --> 00:02:51.060 for all the various subsystems of your computer, 69 00:02:51.060 --> 00:02:53.010 at those necessary voltages. 70 00:02:53.010 --> 00:02:55.470 Your power supply is going to create a lot of heat 71 00:02:55.470 --> 00:02:56.400 when it does this, 72 00:02:56.400 --> 00:02:59.850 and so you're also going to have a fan inside your power supply 73 00:02:59.850 --> 00:03:02.040 to draw air over the transformer 74 00:03:02.040 --> 00:03:03.300 and be able to expel that heat 75 00:03:03.300 --> 00:03:05.430 out the back of that power supply. 76 00:03:05.430 --> 00:03:06.263 This will help 77 00:03:06.263 --> 00:03:08.370 keep the transformer inside the power supply cool 78 00:03:08.370 --> 00:03:11.070 and allow it to work at optimal efficiency. 79 00:03:11.070 --> 00:03:12.690 To install a power supply, 80 00:03:12.690 --> 00:03:14.700 you're simply going to find the location in your case 81 00:03:14.700 --> 00:03:15.720 that will support it. 82 00:03:15.720 --> 00:03:16.553 And generally, 83 00:03:16.553 --> 00:03:18.990 it's going to be inserted using four different screws, 84 00:03:18.990 --> 00:03:20.880 one on each corner of the power supply, 85 00:03:20.880 --> 00:03:22.590 with the power supply plug 86 00:03:22.590 --> 00:03:24.510 hanging out the backside of the case, 87 00:03:24.510 --> 00:03:26.190 and having multiple different connectors 88 00:03:26.190 --> 00:03:28.320 on the inside of the case that can then connect 89 00:03:28.320 --> 00:03:31.050 to your different components from your power supply. 90 00:03:31.050 --> 00:03:33.060 Older power supplies would use cables 91 00:03:33.060 --> 00:03:35.730 that were actually soldered directly into the power supply, 92 00:03:35.730 --> 00:03:37.470 and you'd have all the different connector types 93 00:03:37.470 --> 00:03:38.430 that you might need, 94 00:03:38.430 --> 00:03:40.800 and you'd plug them into your various components. 95 00:03:40.800 --> 00:03:43.200 Some of the new modern power supply units though, 96 00:03:43.200 --> 00:03:46.350 use a form factor that's known as modular PSU 97 00:03:46.350 --> 00:03:48.660 or modular power supply units. 98 00:03:48.660 --> 00:03:50.520 These modular power supply units 99 00:03:50.520 --> 00:03:52.260 allow you to unhook the connectors 100 00:03:52.260 --> 00:03:54.090 and detach them from the unit. 101 00:03:54.090 --> 00:03:56.550 So if you don't need all 15 connectors, 102 00:03:56.550 --> 00:03:58.380 you can unplug the ones you don't need, 103 00:03:58.380 --> 00:04:01.230 and therefore there are less cables inside of your case 104 00:04:01.230 --> 00:04:02.970 connected to your power supply. 105 00:04:02.970 --> 00:04:04.770 This can help improve the airflow and cooling 106 00:04:04.770 --> 00:04:07.860 inside of your case because there's less cables in the way, 107 00:04:07.860 --> 00:04:09.600 and it just clears out a lot of the mess 108 00:04:09.600 --> 00:04:11.520 inside of your computer case. 109 00:04:11.520 --> 00:04:13.800 Now other than that, when you're using a power supply, 110 00:04:13.800 --> 00:04:16.560 it really doesn't matter if it's a modular power supply 111 00:04:16.560 --> 00:04:18.900 or a regular traditional power supply. 112 00:04:18.900 --> 00:04:20.220 Either of these power supply units 113 00:04:20.220 --> 00:04:21.570 are going to operate the same. 114 00:04:21.570 --> 00:04:22.590 The only real difference 115 00:04:22.590 --> 00:04:24.720 is that if you're using a modular power supply, 116 00:04:24.720 --> 00:04:26.970 you can disconnect any of the unneeded cables 117 00:04:26.970 --> 00:04:29.520 to free up space inside of your computer. 118 00:04:29.520 --> 00:04:30.750 Now the last thing we need to talk about 119 00:04:30.750 --> 00:04:32.010 when it comes to power supplies 120 00:04:32.010 --> 00:04:33.570 is the fact that some systems 121 00:04:33.570 --> 00:04:36.150 will actually have more than one power supply. 122 00:04:36.150 --> 00:04:38.640 For example, if you're using a workstation or server 123 00:04:38.640 --> 00:04:40.740 that is critical to your business operations, 124 00:04:40.740 --> 00:04:42.360 you may want to select a motherboard 125 00:04:42.360 --> 00:04:45.570 that supports a redundant power supply configuration. 126 00:04:45.570 --> 00:04:47.850 This will allow you to install two power supply units 127 00:04:47.850 --> 00:04:49.470 into that particular machine, 128 00:04:49.470 --> 00:04:52.470 and then connect dual power to that motherboard. 129 00:04:52.470 --> 00:04:55.470 This way, if one of those power supply units fails, 130 00:04:55.470 --> 00:04:57.720 the other one can continue to carry the load 131 00:04:57.720 --> 00:04:59.790 and keep that machine up and running. 132 00:04:59.790 --> 00:05:00.900 Now for this to work, 133 00:05:00.900 --> 00:05:03.180 you have to have a motherboard that supports it. 134 00:05:03.180 --> 00:05:04.560 And on these type of systems 135 00:05:04.560 --> 00:05:06.690 that support redundant power supplies, 136 00:05:06.690 --> 00:05:08.700 you're going to be able to have those power supplies 137 00:05:08.700 --> 00:05:10.080 plug into a backplane, 138 00:05:10.080 --> 00:05:12.720 and this backplane will then switch between the two sources 139 00:05:12.720 --> 00:05:15.720 as needed to power that particular motherboard. 140 00:05:15.720 --> 00:05:18.270 This means that if one of those power supplies fails, 141 00:05:18.270 --> 00:05:19.620 you can actually replace it 142 00:05:19.620 --> 00:05:21.480 without shutting down that system. 143 00:05:21.480 --> 00:05:23.580 And this will allow you to keep your operations up 144 00:05:23.580 --> 00:05:26.370 and running the entire time because you're dealing 145 00:05:26.370 --> 00:05:28.710 with some kind of a mission critical system in this case, 146 00:05:28.710 --> 00:05:29.670 which is why you bought 147 00:05:29.670 --> 00:05:31.740 a redundant power supply capable motherboard 148 00:05:31.740 --> 00:05:33.150 in the first place. 149 00:05:33.150 --> 00:05:35.550 Now most of us in a regular office environment though 150 00:05:35.550 --> 00:05:37.980 aren't going to be using redundant power supplies. 151 00:05:37.980 --> 00:05:41.400 Instead, each of our cases will have a single power supply 152 00:05:41.400 --> 00:05:43.140 connected directly to our motherboard 153 00:05:43.140 --> 00:05:45.090 to provide power to all of its components, 154 00:05:45.090 --> 00:05:46.440 as well as having additional cables 155 00:05:46.440 --> 00:05:48.030 attached to that power supply 156 00:05:48.030 --> 00:05:50.520 that are connected to things like our processor socket, 157 00:05:50.520 --> 00:05:53.040 our hard drives, and our external graphics cards 158 00:05:53.040 --> 00:05:54.540 if they need additional power.