Welcome to Techal! In this article, we will guide you through the process of designing a transformerless power supply circuit. Whether you’re a technology enthusiast or an engineer, this circuit can be a valuable addition to your electronics projects. We will explain the working principle of the circuit, discuss the required components, and provide a step-by-step guide to building it.
Understanding the Working Principle
Before we dive into the circuit design, let’s understand how it works. The circuit employs a few key components to convert an AC power source to a DC output. It starts by dropping the input voltage using a capacitor. A bleeder resistor across the capacitor ensures its discharge when the input voltage is turned off. Next, a bridge rectifier converts the AC voltage to pulsating DC. To remove the ripple from the output waveform, a filter circuit is added, consisting of a capacitor and a general diode. Finally, a 5.1-volt Zener diode is used to provide a constant voltage.
To calculate the capacitance value for the AC capacitor, use the formula:
Impedance = RMS voltage / Rated currentTo obtain the desired output voltage and current, choose the appropriate capacitance value. In this example, a 1 microfarad capacitor was used to achieve a 6-volt output at 0.1 ampere current.
Building the Circuit
Now that we understand the working principle, let’s move on to building the circuit. The following steps will guide you through the process:
- Solder the diodes onto the PCB. Pay attention to the diode’s band and match it with the indicated band on the PCB. Use four 1N4007 diodes as a bridge rectifier.
- Connect the Zener diode according to the indicated position on the PCB.
- Place a 220-ohm resistor in series with an indicator LED, as marked on the PCB.
- Connect a 220-kilohm resistor in series with resistors R1 and R2.
- Connect an LED with the appropriate polarity. The flat portion of the LED indicates the cathode or negative terminal.
- Connect the connector to the PCB for the 20-volt supply.
- Attach the electrolytic DC capacitor, making sure to connect the positive terminal to the indicated side.
- Connect the AC capacitor, which will provide the 5-volt DC output. This can be done using a 2-pin plug.
- Connect the PCB to a 230-volt AC source using the appropriate connections.
- Connect the power supply output (positive and negative terminals) to a breadboard or the desired load.
Note: When working with high-voltage sources, always take necessary precautions and avoid touching any metal portions while the circuit is connected.
Testing the Circuit
Once the circuit is assembled, turn on the power supply. Measure the voltage across the output terminals using a multimeter set to the DC voltage scale. In this example, a 5.4-volt DC output was obtained. This transformerless power supply is suitable for small loads like motors or LEDs.
FAQs
Q: Can I use this power supply for larger loads?
A: This transformerless power supply is designed for small loads. For larger loads, it is recommended to use a transformer-based power supply.
Q: Is it safe to work with high-voltage sources?
A: Working with high-voltage sources can be dangerous. Always exercise caution and follow safety guidelines when handling high-voltage circuits.
Conclusion
In this guide, we explored the process of designing a transformerless power supply circuit. We discussed the working principle, components, and provided a step-by-step guide to building the circuit. It is important to note that when working with high-voltage sources, safety precautions should be followed. Now you can confidently integrate this power supply circuit into your electronics projects. For more informative articles and exciting technology updates, stay tuned to Techal!
