curso de electrónica básica desde cero | Basic electronics course (#5 circuito serie práctico)

00:15:01
https://www.youtube.com/watch?v=ORGsGaDIlGs

Resumo

TLDRThis instructional video breaks down the process of analyzing a series circuit containing three resistors with color codes indicating resistances of 10k, 1.2k, and 5.6k ohms. It details how to calculate the total resistance and voltage for each component using Ohm's Law. The video also demonstrates practical use of a multimeter for measuring voltage and current in the circuit and explains that the multimeter must be used appropriately to avoid damage. Furthermore, it illustrates the concept of current consistency throughout a series circuit and stresses the importance of properly noting resistor values to prevent design errors.

Conclusões

  • 🔌 Understanding series circuits and how to sum resistances.
  • 📐 Using Ohm's Law (V=IR) for circuit calculations.
  • 🔍 Correct multimeter usage for voltage and resistance.
  • ⚡ Calculating total circuit current from source voltage and total resistance.
  • 📏 Ensuring correct measurement settings to avoid multimeter damage.
  • 🎛️ Importance of accurate resistor value recognition for design.
  • 📊 Measuring individual voltage drops across resistors in a series.
  • 🔄 Consistent current flow in a series circuit despite multiple resistors.
  • ⚠️ Tolerance affects real-world resistor values deviating from theoretical.
  • ♻️ Importance of using consistent units when performing calculations.

Linha do tempo

  • 00:00:00 - 00:05:00

    The presentation discusses a series configuration electric circuit containing three resistors: a 10k (black orange brown), a 1.2k (brown red red), and a 5.6k (green blue red). The task involves finding total resistance and individual voltages for these resistors. The demonstration begins with finding the voltage source using a multimeter, which shows the source voltage as approximately 4.97 volts. The total resistance is calculated by summing up the resistances in kilo-ohms, yielding 16.8 kilo-ohms. This measure aligns with the theoretical calculations, although practical measurements might slightly differ due to resistor tolerance.

  • 00:05:00 - 00:15:01

    Next, the instructor explains how to calculate the total current using Ohm’s Law, dividing the total voltage by the total resistance, resulting in a current of 0.29 milliamperes. This current value is verified through calculations. They proceed to calculate individual voltages across each resistor using the formula V=IR, reinforcing the theoretical values with practical measurement. They confirm calculated values by measuring the circuit under test conditions, explaining that the current remains uniform throughout a series circuit and voltage is divided among components. The summary closes by reinforcing the basic principles of series circuits, stressing the significance of Ohm’s Law.

Mapa mental

Vídeo de perguntas e respostas

  • What is the total resistance in the circuit?

    The total resistance in the circuit is 16.8 kilo ohms.

  • How do you measure the voltage of the power source?

    To measure the voltage of the power source, place the multimeter in the voltage measurement mode, connect the red probe to the red wire and the black probe to the black wire of the power source.

  • What is the voltage of the power source used in the video?

    The power source voltage shown in the video is approximately 4.97 volts.

  • How do you calculate the total current in the circuit?

    The total current is calculated by dividing the voltage of the power source (4.97 volts) by the total resistance (16,800 ohms), resulting in approximately 0.29 milliamps.

  • What should be done before measuring resistances in a circuit?

    Before measuring resistances, ensure that there is no power source connected to the circuit to prevent damage to the multimeter.

  • How should the voltage across each resistor be measured?

    Voltage across each resistor should be measured by placing the multimeter probes across the resistor's terminals while the circuit is powered.

  • Can the polarity of the power source in the circuit affect the measurement?

    In this circuit setup, the polarity of the power source does not affect the measurement.

  • What symbol indicates that a multimeter is set to measure DC voltage?

    A multimeter set to measure DC voltage might show a symbol with a 'V' and a straight line, sometimes accompanied by three dashed lines.

  • How do you change the multimeter's mode for measuring current?

    To measure current, change the multimeter's probe position by placing it in the 'A' slot and set the multimeter to the current measurement mode.

  • Why might the resistance values differ from the theoretical values?

    Resistance may differ from theoretical due to the tolerance of the resistors, often around 5%.

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  • 00:00:04
    In the previous example we had been in a series configuration circuit with the following resistors
  • 00:00:12
    we have a black orange brown resistor that is equivalent to 10 thousand or mine or 10 kilos
  • 00:00:20
    we have a brown resistor in the red red that indicates 1200 or 1.2 kilos
  • 00:00:28
    we have a green one blue red which is equivalent to
  • 00:00:32
    5.6 kilos
  • 00:00:34
    here we can clearly see the three resistances the way they have been connected
  • 00:00:40
    we are going to do a small calculation
  • 00:00:43
    to find the total resistance and each of its voltages then we have the 10k one the
  • 00:00:50
    1200 one and the
  • 00:00:52
    5.6 kilometer one
  • 00:00:53
    Before doing the respective calculations
  • 00:00:56
    we need a voltage source in my case I have a small source you can have
  • 00:01:02
    a cell a charger a battery let's look at what voltage this source has
  • 00:01:09
    we learn our multimeter our multimeter should be on the scale the black tip where it says com
  • 00:01:17
    and the red tip where it says b
  • 00:01:20
    we go to the symbol where it says be and a little line in some cases it comes like this, for example it says
  • 00:01:28
    b for co for cb
  • 00:01:33
    with
  • 00:01:34
    three lines
  • 00:01:36
    and this symbol,
  • 00:01:38
    any of them indicates that it is direct voltage
  • 00:01:40
    or continuous voltage in my case This multimeter has this symbol, as we can see, here
  • 00:01:48
    we go and we are on the 20 volt scale.
  • 00:01:52
    In my case, my multimeter says that it is ago, so
  • 00:01:56
    I pressed this little button and it will tell me that it is CE voltage.
  • 00:02:02
    Not all multimeters
  • 00:02:04
    have the condition of activating. dc or does,
  • 00:02:07
    that is, this multimeter measures alternating voltage and continuous voltage on the same scale. I am going to tell you another multimeter.
  • 00:02:16
    For example, this one,
  • 00:02:19
    here we have the scale
  • 00:02:21
    only of 6 and down here we have the scale only does
  • 00:02:26
    with any of them that we do. the measurement the result will be the same the first thing we must do is
  • 00:02:32
    measure the voltage of the power source that we are going to feed into our circuit to do the calculations
  • 00:02:38
    we place the red tip
  • 00:02:41
    on the red wire and the black tip on the nest wire
  • 00:02:47
    it says that It has 4
  • 00:02:49
    97 volts that will be the voltage of my source. Let's check it with the other multimeter.
  • 00:02:56
    Let's see if it is approximately the same voltage.
  • 00:03:01
    We put it on the scale of 20
  • 00:03:05
    and make the same measurement.
  • 00:03:11
    In this club it reads
  • 00:03:15
    495 or so.
  • 00:03:18
    So that differs. It depends on the multimeter, the quality, the resolution or the battery that the multimeter has.
  • 00:03:26
    With 497, they tell us the following.
  • 00:03:30
    Our calculation
  • 00:03:32
    will mean that we have a source of
  • 00:03:38
    4.97 volts.
  • 00:03:40
    This will be our source. Now we are going to find the
  • 00:03:45
    total resistance. The total resistance. We had already said that It is the sum of the
  • 00:03:50
    resistances and as such they must be added in the same units as we have 10 kilos,
  • 00:03:56
    sorry as we have resistances in kilos we are going to add them in kilos although if we want we can also add them in
  • 00:04:04
    obvious
  • 00:04:06
    design character
  • 00:04:08
    these symbols 1.2 k it is always recommended to do the following
  • 00:04:13
    1 k 2
  • 00:04:16
    telling us the k the point why this is due when you take plans you make
  • 00:04:22
    photocopies at
  • 00:04:25
    different times of the same plan the point tends to get lost therefore
  • 00:04:31
    you would no longer understand 1.2 almost no 12 k and that is something very important in a design so
  • 00:04:38
    get used to having 1 k 2 which would mean 1.2 kilometers
  • 00:04:44
    doing the respective sum we would have the following value we would have 10 k
  • 00:04:52
    + 1.2
  • 00:04:56
    +
  • 00:04:58
    5.6 kilos
  • 00:05:00
    that gives us a total resistance of 16 to 8
  • 00:05:05
    kilos omnium
  • 00:05:07
    that in the previous practice we had also already verified it
  • 00:05:11
    approximately then to measure resistances it is always done without a source, it should not be placed because otherwise
  • 00:05:19
    we can damage our multimeter, remember that the multimeter I know generates enough voltage and current to measure the resistance total
  • 00:05:26
    of our circuit well here we have our multimeter we go to the omnium scale
  • 00:05:33
    according to our calculations of truth 16.8 that is to say that on the 20 kilo scale
  • 00:05:39
    I can perfectly measure my resistance
  • 00:05:43
    so
  • 00:05:44
    we take from end to end
  • 00:05:48
    16.8 kilo or less it should measure so we take
  • 00:05:55
    and We place it
  • 00:05:59
    and the
  • 00:06:01
    16.55 kilos are
  • 00:06:04
    approximately the theoretical value
  • 00:06:06
    Because it differs due to the tolerance of each of the resistors, remember that they are 5% because they are all gold.
  • 00:06:14
    Now what we are going to do is measure each of the voltages,
  • 00:06:19
    for example, more or less than one plus less than two
  • 00:06:24
    plus less than three and we are going to measure the total current of our circuit
  • 00:06:30
    as we already know that the total residence of
  • 00:06:34
    16.8 kilo theoretical news we are going to continue working with that value we have 4
  • 00:06:40
    97 volts and a total resistance of
  • 00:06:44
    16.8 kilo total omnium what we must do is make the division
  • 00:06:49
    divide
  • 00:06:53
    4.97 divided by 16 thousand
  • 00:06:57
    800 men
  • 00:06:58
    then the total iv is equal to the source voltage divided by 16 thousand 800 volts
  • 00:07:07
    are always recommended
  • 00:07:09
    over UFOs in this case here it would be 4
  • 00:07:14
    97 volts divided by omnium the result will be
  • 00:07:19
    amperes as we can see
  • 00:07:22
    there I was putting the voltage
  • 00:07:25
    this result in the calculator
  • 00:07:28
    we give it shift engineering
  • 00:07:31
    and it gives us
  • 00:07:32
    and total is equal to
  • 00:07:37
    0.29
  • 00:07:39
    thousand amperes
  • 00:07:42
    So that is the Total current
  • 00:07:46
    of my circuit
  • 00:07:47
    or I can also have it for example shift ng chip on axis until here it appears in zero and we can observe the value
  • 00:07:55
    in amperes of our of our current then of
  • 00:08:01
    0.30
  • 00:08:02
    29
  • 00:08:03
    amperes
  • 00:08:05
    with those values
  • 00:08:06
    ​​that is to say with that current this current means that it is the one that circulates through the entire circuit or through each of the
  • 00:08:14
    resistive components this same current circulates
  • 00:08:16
    Now we are going to look theoretically and practically at what voltage they are going to give us. Everything, first of all, what we are going to do is
  • 00:08:22
    b1 b1 is equal to the y total times ere 1 b 2 is equal to the y total times ere 2
  • 00:08:30
    b 3 is equal to the and total for ere 3
  • 00:08:35
    being r 1 10,000
  • 00:08:39
    Being
  • 00:08:41
    2200
  • 00:08:44
    and being r3 5600 years times amperes
  • 00:08:51
    it will give us volts so here we have 29 amperes and the result it gives us will be volts
  • 00:08:59
    times
  • 00:09:00
    0.000 29 amperes because it is point 000 29 amperes
  • 00:09:09
    Let's check
  • 00:09:12
    and finally we have
  • 00:09:15
    1.65 volts
  • 00:09:17
    what I did was multiply the total current which is the same because it is a single loop
  • 00:09:24
    multiplied by each of its resistances
  • 00:09:27
    we are going to practically check those values ​​the first thing we must do is power our circuit
  • 00:09:38
    To power In our circuit, in this case there is no problem where we place
  • 00:09:44
    the positive or negative polarity. We simply place it at the ends.
  • 00:09:49
    We take our multimeter on the volt scale.
  • 00:09:54
    We place it on the scale of 20
  • 00:09:57
    and we are going to make the respective measurement of the voltage of each of the resistors
  • 00:10:04
    theoretically says that b 1 is equal to
  • 00:10:06
    2.9 volts, let's check if that value is correct, then the first resistor disc at
  • 00:10:13
    2.9
  • 00:10:15
    Effectively
  • 00:10:17
    292,
  • 00:10:18
    the second resistor says that it should give more or less 0
  • 00:10:22
    34, the value is approximate depending on the quantity of decimals that they use then we place
  • 00:10:29
    0
  • 00:10:30
    35
  • 00:10:32
    Perfectly and finally it says that it is 1.65
  • 00:10:40
    1.64
  • 00:10:41
    how to measure voltage the voltage is measured
  • 00:10:45
    by connecting the ends of the source on the resistance and on each of the components
  • 00:10:51
    I must measure the voltage
  • 00:10:54
    so I measure like this one by one here
  • 00:10:57
    here and here I must not disconnect anything to make the measurement
  • 00:11:03
    we are now going to measure the total current the total current says that it gives me
  • 00:11:09
    0.3 02 29 amperes or 0 29 milliamps
  • 00:11:14
    or it would also be 290 micro amperes to measure the current if necessary Disconnect
  • 00:11:21
    one of the main cables from the source. In this case, because it is series, we are going to measure the total current, even if
  • 00:11:28
    we disconnect any part, the current will always matter to us.
  • 00:11:32
    In this case, we have to be very careful with these multimeters because we have to change the tip.
  • 00:11:38
    We change it here to measure current. The current is measured in sed and volt in parallel.
  • 00:11:45
    Voltage in parallel means
  • 00:11:48
    component by component and current in series. It means disconnecting and placing the leads of my multimeter in series with circuit
  • 00:11:56
    2. We place ourselves on the current scale.
  • 00:12:00
    here it says one and with this small symbol and we are located at the highest scale which is 200 m here we also have
  • 00:12:08
    ac current and that current in this case ce current you can connect this negative cable so we connect the
  • 00:12:16
    cable here and the other the other end where they disconnect
  • 00:12:22
    It measures 0.2 it means that I can go down a little more on the scale of 2000
  • 00:12:30
    It measures
  • 00:12:33
    0.296
  • 00:12:35
    periods according to our calculations It gave us 0 point
  • 00:12:40
    209 0 points
  • 00:12:43
    0.29 milliamps
  • 00:12:45
    we confirm again
  • 00:12:48
    0.29 correct if I change the tips, for example the other way around
  • 00:12:55
    The average negative current
  • 00:12:57
    negative currents there are no negative voltages as there usually are none,
  • 00:13:02
    what happens is that the tips of my multimeter They are backwards,
  • 00:13:06
    this is the reason why it is marking me with a negative value.
  • 00:13:10
    For example, if it says that the series circuit is the current is the same, then we disconnect here,
  • 00:13:17
    here I am going to disconnect, for example, I disconnect the resistor, I am going to place it down here.
  • 00:13:23
    and where I
  • 00:13:24
    disconnected that is where I should measure, then I placed this point at the top and this point I placed at the bottom
  • 00:13:32
    and as you can see, I can measure the same current
  • 00:13:37
    in a series circuit. Let's remember the three fundamental properties,
  • 00:13:42
    first the source voltage
  • 00:13:45
    is divided by each component the sum of the resistances in the total resistance
  • 00:13:51
    and the current is the same in any part of the circuit
  • 00:13:55
    cause current at the same voltage is divided the resistances are added
  • 00:14:00
    with this we finish the practical part of series circuits No matter how many
  • 00:14:07
    resistors you have, the principle will always be the same based on Ohm's law,
  • 00:14:15
    always remember Ohm's law, that is, b is equal to I times r.
  • 00:14:20
    What I did in the exercise was first.
  • 00:14:23
    find total resistance with the total resistance of I found total current and with the total current I found each of two voltages
  • 00:14:32
    I hope you liked this little video in the next video we will talk about parallel circuits and mixed circuits bye bye
Etiquetas
  • Series Circuit
  • Ohm's Law
  • Resistance Calculation
  • Multimeter
  • Voltage Measurement
  • Current Calculation
  • Resistors
  • Electronics
  • DC Voltage
  • Circuit Analysis