How do these resitors not affect the voltage

  • Thread starter snowJT
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In summary, the 6.8 k resistor and the two 10k resistors do not affect the voltage in the circuit since they are connected in parallel to the voltage source. However, they do affect the current going through the diode. To find the voltage drop across the diode, you can use the voltage divider formula by considering the 2.2k resistor as the only component in the circuit. From there, you can find the current going through the diode.
  • #1
snowJT
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In this circuit... how come you just ignore the 6.8 k resistor, and the two 10k to find the voltage at the 2.2 to then get the current across the diode...

do not the 6.8 k resistor, and the two 10k have an effect on the circuit?
 

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  • #2
Since the resistors are connected in parallel to the voltage source, they do not affect the rest of the circuit voltage-wise (unless of course their resistances are set to 0).
 
  • #3
but doesn't it affect the current? because that was what I was asking, not voltage
 
  • #4
Well, you started by asking about voltage (correctly, since for this you need v=ir), but ask yourself this: does current going through the diode also go through those resistors?
 
  • #5
You can also think of it this way. If you remove the diode from the circuit, you will have two terminals, A and B (across the 2.2K resistor). The voltage that the diode or any component will see when connected to these terminals will be the voltage drop across the 2.2K resistor. You can find the voltage drop across that resistor by using the voltage divider formula. And from here, you can go ahead to find the current.
 

1. How do resistors not affect the voltage in a circuit?

Resistors are designed to resist the flow of electric current in a circuit. This means that they create a voltage drop across themselves, which can affect the overall voltage of the circuit. However, as long as the resistance of the resistor is much smaller than the rest of the circuit, the voltage drop across the resistor will be relatively small and will not significantly impact the overall voltage of the circuit.

2. Why do we use resistors in circuits if they can affect the voltage?

Resistors are used in circuits for a variety of reasons, such as limiting current flow, controlling the amount of power dissipated, and dividing voltage. While they may create a voltage drop, this can often be beneficial in achieving the desired functionality of the circuit.

3. How do resistors maintain a constant voltage?

Resistors do not maintain a constant voltage in a circuit. However, they can be used in voltage divider circuits to create a specific voltage output based on the input voltage. This is achieved by utilizing Ohm's Law, which states that the voltage drop across a resistor is equal to the current flowing through the resistor multiplied by its resistance.

4. Can resistors affect the voltage in AC circuits?

Yes, resistors can affect the voltage in AC circuits just as they do in DC circuits. However, since AC circuits have constantly changing voltages and currents, the impact of the resistor on the overall voltage may vary depending on the frequency of the AC signal and the resistance of the resistor.

5. How do resistors affect the voltage in series and parallel circuits?

In series circuits, resistors will have a cumulative effect on the voltage drop across the entire circuit. In parallel circuits, the voltage drop across each resistor will be the same, but the total current flowing through the circuit will be divided based on the resistance of each resistor. Therefore, resistors can affect the voltage in both series and parallel circuits, but in different ways.

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