You add the resistances together to get the total resistance in a series circuit.
Say...
R1=10
R2=12
R3=10
R123=32
The total resistance in a series circuit is simply the sum of the individual resistances of all the resistors connected in that series. This means that if you have multiple resistors, you add their resistance values together to find the total resistance. Mathematically, it can be expressed as ( R_{total} = R_1 + R_2 + R_3 + \ldots + R_n ). The total resistance increases as more resistors are added in series.
In brief, the overall or net resistance changes and the resistors in series and/or parallel can be represented by a single equivalent resistor. If you consider series resistors the equivalent resistance of the series would be: R = R1+R2+ ... +Rx The equivalent resistance of parallel resistors would be: 1/R = 1/R1 + 1/R2 + ... + 1/Rx One rule to always remember when dealing with series and parallel resistors is the voltage across each resistor in parallel will be the same as defined in Kirchhoff Voltage Law and the current across each resistor in series will be the same by Kirchhoff Current Law. More information can be found at this web site. http://physics.bu.edu/py106/notes/Circuits.html
You could use the voltage divider rule to reduce the voltage. Using two resistors in series, the input voltage will drop across each resistor by an amount that is proportionate to the values of the resistors. If the 1st resistor is 10K and the 2nd resistor is 100K, the voltage drop across the 10K will be 10 times LESS than that of the 100K resistor. The total voltage drop across both resistors will be equal to the supplied input voltage. Work out the ratio of voltage you need from the total input voltage and use 2 resistors will that give you the same ratio. Connect the LEDs in parallel with the resistor the gives you the voltage you want. Use a MM to measure the voltage across the resistor before wiring LEDs.
The resistors each have a value of 20 ohms. The way to discover it is to apply Ohm's law. It (Ohm's law) comes in 3 "flavors" that look a bit different but all say exactly the same thing. Here they are: E = I x R [Voltage equals current times resistance.] I = E/R [Current equals voltage divided by resistance.] R = E/I [Resistance equals voltage divided by current.] In these equations, voltage is E, current is I and resistance is R. They are measured in units of volts, amperes (or amps) and ohms, respectively. Your problem gives us an applied voltage of 8 volts and a current flow of 0.2 amps. The formula that probably works best is R = E/I for this one because you have volts and amps. In this case, R = 8/0.2 = 40 ohms. But that's the total resistance in the circuit, and you said that a pair of equal resistors are connected, so the pair of resistors has a total resistance of 40 ohms. The rule for finding total resistance for resistors in series is that we add them up. R1 + R2 = 40 ohms. And since R1 = R2 here, 2 x R1 or 2 = 40 ohms, and R1 or 2 = 20 ohms. Either resistor has a resistance of 20 ohms, and that means they both do. Easy as pie.
A: It just tell you the resistor has a +- % tolerance in its value. Like a 1000 ohms +-5% it can be off + or - that much. That has being the standard for forever however that band is disappearing since most resistors are made +-5% as a rule.
The total resistance in a series circuit is simply the sum of the individual resistances of all the resistors connected in that series. This means that if you have multiple resistors, you add their resistance values together to find the total resistance. Mathematically, it can be expressed as ( R_{total} = R_1 + R_2 + R_3 + \ldots + R_n ). The total resistance increases as more resistors are added in series.
If the resistors are in series, then the total resistance is simply the sum of the resistances of each resistor.
In brief, the overall or net resistance changes and the resistors in series and/or parallel can be represented by a single equivalent resistor. If you consider series resistors the equivalent resistance of the series would be: R = R1+R2+ ... +Rx The equivalent resistance of parallel resistors would be: 1/R = 1/R1 + 1/R2 + ... + 1/Rx One rule to always remember when dealing with series and parallel resistors is the voltage across each resistor in parallel will be the same as defined in Kirchhoff Voltage Law and the current across each resistor in series will be the same by Kirchhoff Current Law. More information can be found at this web site. http://physics.bu.edu/py106/notes/Circuits.html
The voltage across R1 would be 50 volts. This is because the voltage divider rule states that the voltage across each resistor in a series circuit is proportional to its resistance relative to the total resistance in the circuit. In this case, since both resistors are the same (20K), the voltage across each resistor will be half of the total supply voltage.
* resistance increases voltage. Adding more resistance to a circuit will alter the circuit pathway(s) and that change will force a change in voltage, current or both. Adding resistance will affect circuit voltage and current differently depending on whether that resistance is added in series or parallel. (In the question asked, it was not specified.) For a series circuit with one or more resistors, adding resistance in series will reduce total current and will reduce the voltage drop across each existing resistor. (Less current through a resistor means less voltage drop across it.) Total voltage in the circuit will remain the same. (The rule being that the total applied voltage is said to be dropped or felt across the circuit as a whole.) And the sum of the voltage drops in a series circuit is equal to the applied voltage, of course. If resistance is added in parallel to a circuit with one existing circuit resistor, total current in the circuit will increase, and the voltage across the added resistor will be the same as it for the one existing resistor and will be equal to the applied voltage. (The rule being that if only one resistor is in a circuit, hooking another resistor in parallel will have no effect on the voltage drop across or current flow through that single original resistor.) Hooking another resistor across one resistor in a series circuit that has two or more existing resistors will result in an increase in total current in the circuit, an increase in the voltage drop across the other resistors in the circuit, and a decrease in the voltage drop across the resistor across which the newly added resistor has been connected. The newly added resistor will, of course, have the same voltage drop as the resistor across which it is connected.
You could use the voltage divider rule to reduce the voltage. Using two resistors in series, the input voltage will drop across each resistor by an amount that is proportionate to the values of the resistors. If the 1st resistor is 10K and the 2nd resistor is 100K, the voltage drop across the 10K will be 10 times LESS than that of the 100K resistor. The total voltage drop across both resistors will be equal to the supplied input voltage. Work out the ratio of voltage you need from the total input voltage and use 2 resistors will that give you the same ratio. Connect the LEDs in parallel with the resistor the gives you the voltage you want. Use a MM to measure the voltage across the resistor before wiring LEDs.
The en passant rule was added to chess in the 15th century.
Vectors are added by head to tail rule.
The resistors each have a value of 20 ohms. The way to discover it is to apply Ohm's law. It (Ohm's law) comes in 3 "flavors" that look a bit different but all say exactly the same thing. Here they are: E = I x R [Voltage equals current times resistance.] I = E/R [Current equals voltage divided by resistance.] R = E/I [Resistance equals voltage divided by current.] In these equations, voltage is E, current is I and resistance is R. They are measured in units of volts, amperes (or amps) and ohms, respectively. Your problem gives us an applied voltage of 8 volts and a current flow of 0.2 amps. The formula that probably works best is R = E/I for this one because you have volts and amps. In this case, R = 8/0.2 = 40 ohms. But that's the total resistance in the circuit, and you said that a pair of equal resistors are connected, so the pair of resistors has a total resistance of 40 ohms. The rule for finding total resistance for resistors in series is that we add them up. R1 + R2 = 40 ohms. And since R1 = R2 here, 2 x R1 or 2 = 40 ohms, and R1 or 2 = 20 ohms. Either resistor has a resistance of 20 ohms, and that means they both do. Easy as pie.
The offside rule was added to soccer in 1863 when the Football Association in England established the first official rules of the game.
by head to tail rule they are added
No. A series is just a list of numbers, with some kind of 'rule' that tells you how you get from one number to the next one. What you have in your question looks like a sum, all ready to get added up.