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Capacitor Types - electrolytic, ceramic, tantalum, plastic film

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Language: en

00:00:06.410
capacitors appear in all types of
00:00:08.690 00:00:08.700 electronic equipment from computer-based
00:00:10.580 00:00:10.590 equipment to radios televisions Wi-Fi
00:00:13.580 00:00:13.590 routers cell phones in fact almost
00:00:15.709 00:00:15.719 without exception any piece of
00:00:17.660 00:00:17.670 electronic equipment will have many
00:00:19.970 00:00:19.980 capacitors inside it big small fat thin
00:00:24.140 00:00:24.150 cylindrical rectangular capacitors come
00:00:27.080 00:00:27.090 in all shapes and sizes
00:00:28.670 00:00:28.680 they also used different dielectrics and
00:00:31.400 00:00:31.410 different methods of construction and
00:00:33.410 00:00:33.420 this changes their performance it's
00:00:36.680 00:00:36.690 important to understand the differences
00:00:38.690 00:00:38.700 between the different types of capacitor
00:00:40.490 00:00:40.500 because some work better in some areas
00:00:43.010 00:00:43.020 than others
00:00:43.639 00:00:43.649 in fact some won't work in some places
00:00:45.950 00:00:45.960 at all where other types will so it's
00:00:48.979 00:00:48.989 important to understand what the
00:00:50.569 00:00:50.579 different types of capacitor are this is
00:00:53.900 00:00:53.910 the circuit symbol for a capacitor in
00:00:56.270 00:00:56.280 this case it is non polarized and here
00:00:59.599 00:00:59.609 we see a polarized one a polarized
00:01:02.720 00:01:02.730 capacitor must have any DC voltage
00:01:04.880 00:01:04.890 across it in the right sense positive at
00:01:07.370 00:01:07.380 one end and negative at the other the
00:01:10.340 00:01:10.350 dielectric or the material between the
00:01:12.380 00:01:12.390 two capacitor plates is very important
00:01:14.870 00:01:14.880 it governs many of the capacitors
00:01:17.240 00:01:17.250 properties things like capacitance
00:01:19.399 00:01:19.409 levels voltage withstand temperature
00:01:21.679 00:01:21.689 coefficient and many other things there
00:01:24.920 00:01:24.930 are a number of types of capacitor that
00:01:26.690 00:01:26.700 are more common than others
00:01:27.890 00:01:27.900 and we're going to be taking a look at
00:01:29.719 00:01:29.729 these possibly the most common of the
00:01:32.179 00:01:32.189 aluminium electrolytic tantalum ceramic
00:01:35.270 00:01:35.280 and finally plastic film capacitors
00:01:37.480 00:01:37.490 beyond these there are several other
00:01:39.590 00:01:39.600 types like silver mica glass super
00:01:42.440 00:01:42.450 capacitors and some others but these
00:01:44.660 00:01:44.670 aren't nearly so common so we won't be
00:01:46.969 00:01:46.979 covering them in this video first up is
00:01:49.460 00:01:49.470 the electrolytic capacitor this type
00:01:51.889 00:01:51.899 normally comes in a metal can with an
00:01:54.139 00:01:54.149 outer plastic sheath they come in a
00:01:56.359 00:01:56.369 variety of sizes with a good range of
00:01:58.639 00:01:58.649 values they're also available in both
00:02:01.100 00:02:01.110 lead 'add and surface mount packages the
00:02:04.310 00:02:04.320 markings on the capacitor are printed on
00:02:06.380 00:02:06.390 the outer sheath in this first example
00:02:08.809 00:02:08.819 it's possible to see the value itself
00:02:10.550 00:02:10.560 and also the working voltage
00:02:13.330 00:02:13.340 also very important is the mark for the
00:02:15.490 00:02:15.500 negative terminal to ensure it's
00:02:17.380 00:02:17.390 connected the right way round in the
00:02:20.290 00:02:20.300 next example the value and voltage are
00:02:22.270 00:02:22.280 given along with the temperature range
00:02:23.920 00:02:23.930 and the maximum current the current
00:02:26.650 00:02:26.660 rating is very important for
00:02:28.180 00:02:28.190 applications like using power supplies
00:02:30.610 00:02:30.620 where lots of current may be flowing
00:02:32.970 00:02:32.980 let's summarize the main characteristics
00:02:36.220 00:02:36.230 of the electrolytic capacitor first it
00:02:38.979 00:02:38.989 is polarized having positive and
00:02:41.080 00:02:41.090 negative terminals and it must be
00:02:43.270 00:02:43.280 connected the right way round otherwise
00:02:45.309 00:02:45.319 damage may result aluminium electrolytic
00:02:48.910 00:02:48.920 snore Mele have large values of
00:02:50.770 00:02:50.780 capacitance anywhere from about a micro
00:02:53.949 00:02:53.959 farad right up to values of well I think
00:02:56.710 00:02:56.720 the largest I've seen is around 47
00:02:58.870 00:02:58.880 thousand microfarads they typically have
00:03:02.350 00:03:02.360 working voltage values up to figures of
00:03:04.960 00:03:04.970 around 50 volts but some for use in high
00:03:08.020 00:03:08.030 voltage supplies may be as high as 350
00:03:11.050 00:03:11.060 volts they have a high ripple current
00:03:13.809 00:03:13.819 capability which makes them ideal for
00:03:16.300 00:03:16.310 use in power supplies but on the
00:03:18.759 00:03:18.769 downside they have a relatively high
00:03:20.530 00:03:20.540 level of leakage and a poor value of
00:03:23.080 00:03:23.090 Tolerance or accuracy often plus 50% and
00:03:27.580 00:03:27.590 minus 20% which rules them out of
00:03:30.130 00:03:30.140 precision applications and another
00:03:32.710 00:03:32.720 limitation is their high frequency
00:03:34.539 00:03:34.549 performance they're not normally used
00:03:36.610 00:03:36.620 for frequencies much above 100 kilohertz
00:03:38.530 00:03:38.540 and use with radio frequencies is
00:03:40.990 00:03:41.000 definitely out another popular type of
00:03:44.559 00:03:44.569 capacitor is the tantalum capacitor
00:03:46.750 00:03:46.760 these capacitors are much smaller than
00:03:49.090 00:03:49.100 electrolytic SAR seen here the lead
00:03:51.280 00:03:51.290 adverse being in the form of a bead
00:03:53.460 00:03:53.470 surface mount versions are also used a
00:03:55.900 00:03:55.910 lot especially these days with mass
00:03:57.819 00:03:57.829 production the markings on lead ones are
00:04:01.390 00:04:01.400 generally in the form of figures these
00:04:03.309 00:04:03.319 days although a color coding scheme was
00:04:05.590 00:04:05.600 used some years ago markings are
00:04:08.140 00:04:08.150 normally quite obvious being the value
00:04:09.970 00:04:09.980 working voltage and a polarity
00:04:12.039 00:04:12.049 indication for surface mount capacitors
00:04:15.370 00:04:15.380 the value is generally marked in terms
00:04:17.229 00:04:17.239 of the significant figures and a
00:04:19.240 00:04:19.250 multiplier so in this instance the value
00:04:22.060 00:04:22.070 is 47 times 10 to the power of 5
00:04:25.390 00:04:25.400 point-7 microfarads sometimes the values
00:04:29.110 00:04:29.120 may be marked more directly and often
00:04:31.450 00:04:31.460 the working voltage is added and of
00:04:33.670 00:04:33.680 course the bar across one end indicates
00:04:36.100 00:04:36.110 the positive terminal in summary the
00:04:39.760 00:04:39.770 main characteristics of the tantalum
00:04:41.740 00:04:41.750 capacitor are that it is polarized like
00:04:44.379 00:04:44.389 the electrolytic requiring it to be
00:04:46.540 00:04:46.550 fitted into the circuit in a particular
00:04:48.129 00:04:48.139 way they have a high level of
00:04:50.499 00:04:50.509 capacitance in a very small volume
00:04:51.969 00:04:51.979 making them ideal for many of today's
00:04:54.430 00:04:54.440 miniaturized pieces of electronic
00:04:56.590 00:04:56.600 gadgetry they're only used in low
00:04:59.500 00:04:59.510 voltage applications typically maximum
00:05:02.140 00:05:02.150 working voltages available are around 35
00:05:04.629 00:05:04.639 volts or a little more unfortunately
00:05:07.360 00:05:07.370 they have a low leakage level what they
00:05:10.060 00:05:10.070 don't like is reverse voltages or /
00:05:12.790 00:05:12.800 voltages they can explode if these are
00:05:15.279 00:05:15.289 exceeded oh and they cannot take high
00:05:18.460 00:05:18.470 ripple currents as well so they're not
00:05:20.439 00:05:20.449 used for power supply smoothing ceramic
00:05:24.040 00:05:24.050 capacitors form the mainstay of many
00:05:25.870 00:05:25.880 designs the lead adverse have a number
00:05:28.600 00:05:28.610 of slightly different formats but in
00:05:30.580 00:05:30.590 most cases they're reasonably similar
00:05:32.140 00:05:32.150 the surface mount versions are widely
00:05:34.540 00:05:34.550 used in mass-produced equipment they're
00:05:36.730 00:05:36.740 very cheap and easy to manufacture and
00:05:39.040 00:05:39.050 are seen on almost every surface mount
00:05:41.260 00:05:41.270 board markings are normally only seen on
00:05:44.350 00:05:44.360 the lead adverse because the surface
00:05:46.540 00:05:46.550 mount ones are normally too small we
00:05:49.120 00:05:49.130 have a couple of examples of leader
00:05:50.620 00:05:50.630 versions here this one shows the value
00:05:53.320 00:05:53.330 and the voltage and this one shows not
00:05:55.960 00:05:55.970 only the value in the working voltage
00:05:57.339 00:05:57.349 but also the type of ceramic dielectric
00:06:00.399 00:06:00.409 and the tolerance so to summarize the
00:06:04.060 00:06:04.070 main characteristics of the ceramic
00:06:05.980 00:06:05.990 capacitor include the fact that it is
00:06:08.110 00:06:08.120 not polarized the values range from a
00:06:11.110 00:06:11.120 few Pico farad's right up to around
00:06:13.330 00:06:13.340 about probably 0.1 / microfarad the
00:06:17.200 00:06:17.210 working voltage may be low for those
00:06:19.089 00:06:19.099 designs using low voltages although
00:06:21.339 00:06:21.349 values of a kilovolt or more are
00:06:23.350 00:06:23.360 available for high voltage applications
00:06:26.129 00:06:26.139 there are several different forms of
00:06:28.629 00:06:28.639 ceramic dielectric that can be used
00:06:30.510 00:06:30.520 these vary in their properties some
00:06:32.920 00:06:32.930 enabling accurate tolerances to be
00:06:34.810 00:06:34.820 quoted last others offer high
00:06:36.940 00:06:36.950 capacitance levels for a given volume
00:06:39.460 00:06:39.470 these capacitors are very successful and
00:06:41.950 00:06:41.960 they're widely used in leading and
00:06:44.070 00:06:44.080 surface-mount versions ceramic
00:06:46.930 00:06:46.940 capacitors are also widely used for
00:06:49.000 00:06:49.010 radio frequency or RF applications where
00:06:51.970 00:06:51.980 they're able to provide excellent
00:06:53.680 00:06:53.690 performance
00:06:54.690 00:06:54.700 another type of capacitor that is widely
00:06:57.400 00:06:57.410 used is the plastic film capacitor
00:07:00.120 00:07:00.130 several different types of plastic film
00:07:02.740 00:07:02.750 may be used each having slightly
00:07:04.810 00:07:04.820 different characteristics names like
00:07:07.210 00:07:07.220 polyester polystyrene and a host of
00:07:09.850 00:07:09.860 other types are available in terms of
00:07:12.790 00:07:12.800 their salient features these capacitors
00:07:15.310 00:07:15.320 may use a metallized film or a plastic
00:07:18.010 00:07:18.020 film with foil between the layers to
00:07:19.870 00:07:19.880 form the plates the exact properties are
00:07:23.230 00:07:23.240 dependent upon the type of film used
00:07:25.800 00:07:25.810 values may range from around 100 pick
00:07:28.810 00:07:28.820 farad's up to possibly even 10
00:07:31.060 00:07:31.070 microfarads they may have working
00:07:33.940 00:07:33.950 voltages between 10 volts up to as much
00:07:36.700 00:07:36.710 as 2 kilovolts generally these
00:07:39.790 00:07:39.800 capacitors are used as leading devices
00:07:41.830 00:07:41.840 although some surface mount versions are
00:07:44.260 00:07:44.270 available but they're not as common as
00:07:46.600 00:07:46.610 other types because there are issues
00:07:48.340 00:07:48.350 with the high temperatures used for
00:07:50.320 00:07:50.330 soldering surface mount components there
00:07:53.470 00:07:53.480 we have it a whirlwind review of some of
00:07:55.900 00:07:55.910 the major types of capacitor the
00:07:58.210 00:07:58.220 electrolytic capacitor polarized and
00:08:00.670 00:08:00.680 with high values but low tolerance and
00:08:03.070 00:08:03.080 high leakage the tantalum which provides
00:08:05.530 00:08:05.540 a large amount of capacitance in a small
00:08:07.540 00:08:07.550 space but again polarized and it doesn't
00:08:10.330 00:08:10.340 like any misuse the ceramic capacitor
00:08:12.880 00:08:12.890 which is the workhorse of many designs
00:08:14.770 00:08:14.780 and finally the plastic film capacitor
00:08:17.409 00:08:17.419 with a variety of different types of
00:08:19.210 00:08:19.220 film for the dielectric

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