How Do I Convert High DC Voltage to Low? Diodes & Resistors

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High Dc is required for certain devices and components to operate and function properly because high DC voltage provides enough pressure, so the components can draw the current they need; however, you may want to connect a low voltage device to a high DC voltage source, so you have to convert the high DC voltage to a low DC voltage.

How Do I Convert High DC Voltage to Low?

To convert a high DC voltage to a low dc voltage, you can use several methods, for example:

  • Resistors
  • Silicon Diodes
  • Zener Diode
  • Voltage Divider Circuit

Each method has its upsides and downsides; you can decide which method to use based on your needs and the circuit components.

Resistors

You can use resistors to convert high DC voltage to low DC voltage by connecting a resistor that lowers the voltage around the device; for example, if the voltage around the device is 12V, you can use a resistor that the voltage across its terminals is 4V to lower the voltage around the device by 4V.

You can use a resistor to reduce high voltage through these steps:

  1. Bring a multimeter, and adjust the multimeter to DC voltage mode.
  2. Use the multimeter probes to measure the voltage around the device you want to connect it to reduced voltage.
  3. After measuring the device’s voltage, you can write it down to check it later after you connect the resistor.
  4. Grab a resistor of a known voltage, the voltage of the resistor should equal the amount you want to reduce from the high voltage you have.
  5. Connect the resistor leads to the circuit; the device and the resistor should be connected in series.
  6. Connect the circuit to the voltage source, and bring the multimeter again.
  7. Use the multimeter to measure the voltage across the device and compare the voltage to the one you measured before. You are done if the voltage has changed to the value you wanted.
  8. If the voltage is reduced but not to the value to wanted, you need to check the voltage across the resistor you used to ensure that the voltage across it is the amount you want to reduce.

The Upside of this method is that it’s very easy to apply; meanwhile, the downside is that you can’t use the separate systems, which means that the current passing through the circuit is the current passing the resistor and the device.

Diodes

Silicon diodes have a drop voltage of 0.7V when a current is passing through them; for example, if you connect four diodes, they would reduce the voltage by 0.7*4= 2.8V; this method can be used if you want to convert a high DC voltage to a slightly lower DC voltage; however, you can use multiple diodes to reach the required value if you want.

The Upside of this method is that silicon diodes are widely available and have easy installation; meanwhile, the downside is that they drop the voltage by a small amount, so you need a large number of silicon diodes to reduce a large amount voltage.

Zener Diodes

Zener diodes have a special design that can reduce reversed voltage to a certain value, in addition, Zener diodes have low cost which makes them a great option when it comes to voltage regulators.

To use Zener diodes as a voltage regulator to convert high DC voltage to low DC voltage, you have to follow these steps:

  1. First, you need to calculate the resistance of the resistor, which will protect the diode from the excess current by dividing the maximum current that will pass through this certain area by the regulated voltage. For example, if the current is 0.01 amperes and the voltage is 20V, the resistance will be 2000 ohms.
  2. Next, calculate the minimum wattage for the circuit by raising the current to the power two, and then multiply the result with the resistance and for safety, double it, so for example, (.02)^2 x 2,000 x 2 = 1.6, which means that a 1.6 watt resistor (1.6 watts) will be suitable for protecting the diode.
  3. You have to buy a resistor with these specific characteristics and a Zener diode that reduces the voltage by the amount required from any hardware store.
  4. Install the Zener diode to a solderless breadboard by connecting its cathode and anode to different columns.
  5. Connect one of the resistor’s leads to the anode of the Zener diode by a piece of wire, and connect the resistor’s other lead to an empty column from the board’s columns. The last wire should be set to share the same column as the resistor.
  6. Connect the wire’s other end you used to the DC voltage source’s positive terminal, and connect one end of the wires connected to the diode to the negative terminal of the DC voltage source.
  7. Use the cathode and anode wires to supply the regulated voltage to the circuit you want, the cathode will be the positive terminal, and the anode will be the negative terminal.

Voltage Divider

A voltage divider is a simple electrical circuit used to divide the voltage to a lower value; the most simple voltage divider consists of two resistors connected in series and having a jumper wire connected between them.

The jumper wire is responsible for the output voltage; it’s used to connect the circuit that needs a lower voltage. To construct a voltage divider circuit that consists of two resistors, you have to follow these steps:

  1. Bring two resistors that are suitable for generating the required value.
  2. Connect one of the terminals of the first resistor to the positive terminal of the DC voltage source, and connect the other terminal of the first resistor to the first terminal of the second resistor.
  3. The second terminal of the second resistor should be connected to the negative terminal of the DC source.
  4. Now that the voltage divider circuit has been created, the voltage divider circuit, next you should connect two wires between the two resistors; the wires should be connected to the smallest resistor; these wires are then used to supply the reduced voltage to the circuit.

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What Is the Easiest Way To Convert a High DC Voltage to a Low DC Voltage?

The easiest way to convert a high DC voltage to a lower DC voltage is using a voltage regulator, which is a Zener diode, because the Zener diodes provide a constant voltage supply.

Zener diodes can regulate the voltage to any value you need, unlike silicon diodes that only offer 0.6V – 0.7V per diode; therefore, you need several diodes to achieve a huge voltage drop.

Does High DC Voltage Need to be Converted to Low DC Voltage?

No, some devices are designed to work on high voltages; if they are connected to a lower voltage, they will have no enough power to operate; meanwhile, some devices require low voltage to operate because if they are connected to a high voltage, it will force them to draw more current than what they are supposed to draw.

Therefore, high DC voltage must be converted to low DC voltage only if the device or the component requires it; this way, you can protect the device from drawing excess current, which can burn the components.

Conclusion

To sum up, you can convert a high DC voltage to a low dc voltage; you can use several methods, for example:

  • Resistors
  • Silicon Diodes
  • Zener Diode
  • Voltage Divider Circuit

Each method has its upsides and downsides; you can decide which method to use based on your needs and the circuit components.

There are several ways to convert a high DC voltage to a low DC voltage; however, one of the easiest ways is using a voltage regulator, which is a Zener diode, because the Zener diodes provide a constant voltage supply. Zener diodes can regulate the voltage to any value you need, unlike silicon diodes that only offer 0.6V – 0.7V per diode.

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