Electricity | |
| Author | Message | |
Anonymous
225 | the higher the resistor's value, the higher the voltage; and the lower the current flowing. |
Anonymous
225 | Calculation of voltage depends on the circuit,not that an introduction of an elemnt will increase or decrease it
Its very well explained here by "liljay22776" |
Anonymous
225 | By Ohm's law V=IR where,
V=Voltage
I=Current
R=Resistance
or R=V/I thus Resistance is inversely proportional to Current "Across the resistor"
Meaning Resistance decreases Current.
Resistance simply means, Resistance to Current... ;)
Is it clear now..? |
liljay22776
3 | Now that being said, you can place a resistor in parallel with the load to divide the available current to the load. When this is done, the current SPLITS among the two branches that you have made. Whenever this is done, though, the resistance is reduced. The resistance between the two branches IS ALWAYS LESS THAN THE RESISTANCE OF THE SMALLEST LOAD.
Likewise, you can place a resistor in series with the load to divide the voltage drop bteween the two loads. When this is done, you get a separate voltage drop across each load. Be careful doing this, because if you drop too much voltage across the added load, the intended load might not function (or light will not burn). This is why ALL THE CIRCUITS IN ALL HOMES AND MOST COMMERCIAL BUILDINGS ARE WIRED IN PARALLEL. |
liljay22776
3 | In a series circuit, the CURRENT FLOW remains the same throughout the circuit. The VOLTAGE, however , drops according to the resistance of each load. Therefore, the VOLTAGE DROP in a device is dependent upon the current flowing through the load (or device), and the resistance (or impedance if an AC circuit) of the load. This is also known as a VOLTAGE DIVIDER (because you divide the total voltage among all the loads in a series circuit).
In a parallel circuit, things seem to switch around. The voltage drop remains the same across the total load of each branch. The current flow, however, will be different in each branch. The current flow in each branch is dependent upon the voltage drop across the whole branch and the total resistance(or impedance ) of the branch. This concept is an example of a CURRENT DIVIDER. You will divide the total current through all the branches of the circuit.
|
Anonymous
225 | It depends how it's wired into the circuit. If it's in series (with other resistors or a load, like a light or motor) it drops the Voltage. If it's wired in parallel, it drops the Current (beacuse some current flows through the resistor, some through the parallel load).
HTH. |
Anonymous
225 | How do you find out by how much the voltage drops with a resister? |
Anonymous
225 | resistors reduce the current |
Anonymous
225 | resistors reduce the current |
Anonymous
225 | resistors reduce the current |
Anonymous
225 | resistors reduce the current |
Anonymous
225 | Resistors oppose/limit Voltage and Current so yes it does reduce current and "takes" part of the voltage onto itself, which is nice if you want to use the voltage drop across the resistor |
emfb
1 | resistors provide resistance to the flow of current.
In the example of a led & resistor circuit the led will drop 1.4v leaving 3.6 volts across the resistor. Current is calculated by I = 3.6v/R. So for a 1K ohm resistor the series current in the circuit would be 3.6ma
If you were to substitute a variable resistor in the circuit, the voltage drop across the var resistor as the resistance is changed would for the most part remain constant (first approx.) but current would vary. This is useful to allow the brightness of the led to be changed by varying the series current.
Remember though too much current will burn out your led. Which is ultamatly why a resistor is needed in the first place... to limit current.
|
Anonymous
225 | Then why does a led that needs say 1.4 volts work when you use a 5 volt source and a resister. If the resister doesn't drop the voltage surely 5 volts is reaching the resistor. |
Anonymous
225 | Ohm's law = E
---
I * R
E = Volts
I = Ampere
R = Resistance
As you increase resistance, your amperage drops. Voltage stays the same. |
Anonymous
225 | I have always been confused byt this, do resisters decrease the voltage or the current or both or what? |
|
| last thread - view all threads - next thread |
