Design of a Voltage Regulator

In summary, the conversation discusses the design of a simple voltage regulator using only resistors to deliver 7.00 volts to a load with a 10v power supply. The circuit includes 1 resistor in series with two parallel resistors, with the last parallel resistor being Rload. Through experimentation, it was found that a 100 ohm resistor for R2 and a 40 ohm resistor for R1 would work. However, the problem is determining the value of R1 through calculation. The conversation suggests using the formula (91/(91+R1)) * 10 = 7.0 to determine R1. Alternatively, one could pick a value for Rload and set R2 to the same value, making their
  • #1
bengaltiger14
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0
I am to design a simple voltage regulator(resistors only) to deliver 7.00 volts to a load with a 10v power supply. The circuit will be 1 resistor in series with two parallel resistors. The last parallel resistor being Rload (which can vary from 1000 to 1500 ohms).

Through experiment, I found that I could use a 100 ohm resistor for R2 which would make R1 a 40 ohm resistor. My problem is determining the value for R1 through calculation.

R2 and Rload at 1000 ohms is 91 ohms. So I use the formula: (91/(91+R1)) * 10 = 7.0. Is the right in determing R1? If you plug 40 for R1 is works.

I just need calculations proving this and I think I am having algebra problems solving for R1.
 
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  • #2
I think the easiest way to do this is just pick a value for Rload and set R2 to the same value. So their resistance is effectively half of one of their values. For simplicity i chose 1k ohms.

Then since you know you want the value across them to be 7 volts use ohms law to solve for the current. I = V / R. I = 7v / 500 ohms this gives 14mA.

To solve for the value of the first resistor use ohms law again in the form of R = V / I. We can do this because we know the current flowing through the series circuit and we know we want 3V across the first resistor.

R = 3V/ 14mA, R = 214 ohms.
 
  • #3


I would first like to commend you on your experimentation and efforts in designing a voltage regulator. It is important to understand the principles and calculations behind the design in order to ensure its effectiveness and reliability.

In terms of determining the value for R1, the formula you have used is correct. The voltage divider equation, Vout = (R2/(R1+R2)) * Vin, is commonly used to calculate the output voltage in a voltage regulator circuit. In this case, Vin is 10V and Vout is 7V, so the equation becomes 7 = (R2/(R1+R2)) * 10.

Using your values of R2 = 100 ohms and Rload = 1000 ohms, we can rearrange the equation to solve for R1:

R1 = (R2 * Vin)/(Vout - Vin) = (100 * 10)/(7 - 10) = 1000 ohms

This confirms that the value of R1 should be 1000 ohms when R2 is 100 ohms and Rload is 1000 ohms. When Rload varies from 1000 to 1500 ohms, the value of R1 will also vary accordingly.

To further validate your calculations, you can also use the power equation to check if the power dissipated by R1 is within a safe range. The power dissipated by R1 can be calculated as P = (Vin^2)/(R1+R2). In this case, P = (10^2)/(1000+100) = 0.1W, which is a safe value for most resistors.

In conclusion, your calculations and algebra are correct in determining the value of R1 for your voltage regulator circuit. It is important to double check your calculations and also consider factors such as power dissipation to ensure the effectiveness and safety of your design. Keep up the good work in your scientific endeavors!
 

1. What is a voltage regulator?

A voltage regulator is an electronic device that is used to maintain a constant output voltage level despite changes in input voltage or load conditions. It is commonly used in electronic circuits to provide a stable power supply for other components.

2. Why is a voltage regulator important?

A voltage regulator is important because it ensures that the electrical devices in a circuit receive a constant and stable voltage supply. This helps to prevent damage to the devices and ensures they function properly.

3. What are the main components of a voltage regulator?

The main components of a voltage regulator include a reference voltage, a feedback circuit, and a control element such as a transistor or integrated circuit. The reference voltage sets the desired output voltage, while the feedback circuit measures the output voltage and adjusts the control element to maintain the desired level.

4. How does a voltage regulator work?

A voltage regulator works by comparing the output voltage to a reference voltage. If the output voltage is lower than the reference voltage, the control element increases the voltage. If the output voltage is higher than the reference voltage, the control element decreases the voltage. This continuous adjustment maintains a constant output voltage level.

5. What are the different types of voltage regulators?

There are three main types of voltage regulators: linear regulators, switching regulators, and shunt regulators. Linear regulators use a control element to regulate the output voltage, while switching regulators use a switching element to regulate the output voltage. Shunt regulators are used to regulate the voltage by diverting excess current away from the load.

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