WEBVTT 00:00.060 --> 00:05.070 You're going to run into a few questions that might require you to know the difference between electromagnetic 00:05.070 --> 00:11.190 interference versus radio frequency interference versus electrostatic discharge that are known as EMI 00:11.190 --> 00:15.990 RFI and ESD So let's just take a moment and make sure we're comfortable with all three of these. 00:15.990 --> 00:18.380 Let's start with electromagnetic interference. 00:22.530 --> 00:28.120 Just about every electronic device out there emits some form of radiation. 00:28.140 --> 00:33.720 Now this radiation can be in the radio range it could possibly be in the infrared. 00:33.720 --> 00:34.440 Who knows. 00:34.560 --> 00:38.960 But the problem is is that they emit radiation and this can cause problems. 00:38.970 --> 00:44.990 Generically we call all this electromagnetic interference when it's interfering with somebody else. 00:45.000 --> 00:50.280 Now if it's only in the radio range like it with this wireless access point in that case we call it 00:50.370 --> 00:52.470 radio frequency interference. 00:52.680 --> 00:56.550 The bottom line is is that we need to be able to do something about it. 00:56.550 --> 00:58.080 Number one we isolate. 00:58.080 --> 01:03.200 We try to move the stuff away from the things that it's causing the interference from. 01:03.230 --> 01:06.880 The second thing we're going to do is we're going to shield our devices. 01:06.890 --> 01:13.160 So for example here's a piece of shielded ethernet cable that's designed to protect us from EMI and 01:13.160 --> 01:14.120 RFI. 01:14.510 --> 01:22.010 Equally we can do separate circuits and a lot of situations will actually see for example this electric 01:22.010 --> 01:29.370 motor which has its own separate electric current which helps to protect everybody else from EMI. 01:29.370 --> 01:33.910 Now EMI and RFI are based on radiation. 01:33.920 --> 01:39.080 However I want to talk about one more thing that's based on good ole electricity and that's electrostatic 01:39.080 --> 01:39.980 discharge. 01:43.950 --> 01:47.540 Everything on earth has some amount of electrical charge. 01:47.550 --> 01:48.900 Now we've all felt this. 01:48.900 --> 01:54.000 Anybody who's walked up to a door knob on a dry day wearing a pair so pajamas while petting their cat 01:54.300 --> 01:57.870 has definitely felt a little bit of electrostatic discharge. 01:57.870 --> 02:03.150 Now while this is an inconvenience for humans if we do the exact same thing to a piece of electronics 02:03.480 --> 02:05.480 it can absolutely destroy it. 02:05.640 --> 02:10.070 So what we need to do is protect ourselves from ESD. 02:10.170 --> 02:13.190 Number one we try to keep everything at the same potential. 02:13.260 --> 02:15.510 Here's a typical ESD wrist strap. 02:15.510 --> 02:21.300 The whole idea behind using this device is we stamp one end into the workpiece and then we keep the 02:21.300 --> 02:23.120 other part on our wrist. 02:23.220 --> 02:25.800 That way we stay at the same potential. 02:25.890 --> 02:32.940 Also just about any form of electronic device for example this USP thumb drive has built in anti ESD 02:32.940 --> 02:37.650 circuitry to protect it in case we do get a little bit of a charge. 02:37.650 --> 02:44.670 The important thing is that you recognize the difference between EMI versus RFI versus ESD and also 02:44.670 --> 02:51.150 make sure you understand the security features we can do to keep our availability of our electronic 02:51.150 --> 03:09.160 equipment really high.