Even if the initial power source is DC such as a battery, our electronics and appliances they generally need AC power to work.
Because of this devices like phone chargers and UPS systems that need battery backups require a unique component known as an inverter.
An inverter changes DC power to AC power.
This article teaches how to build a simple 100 watt inverter circuit using a common chip called the IC 4047.
It explains how the inverter works and how one should build it.
How the Circuit Works:
Parts List:
| Category | Component | Quantity |
|---|---|---|
| Resistors | 390k 1/4W CFR | 1 |
| 330Ω 1/4W CFR | 1 | |
| 220Ω 1/4W CFR | 2 | |
| Preset | 100k Preset | 1 |
| Capacitor | PPC 10nF Capacitor | 1 |
| Semiconductors | IC 4047 | 1 |
| IRFZ44 MOSFET | 2 | |
| Transformer as per diagram | 1 | |
| 12V Battery | 1 |
The simple 100 watt inverter circuit using the 4047 IC operates as follows:
The 4047 IC is the central element of the circuit and is set up as an astable multivibrator.
This configuration generates alternate pulses at pins 10 and 11 of the IC 4047.
The rate of pulse generation is adjustable using a potentiometer VR1 and a capacitor C1.
The drain pins of the Mosfets are connected to the secondary winding of the transformer.
Also the source pins of the Mosfets are connected to the negative terminal of the battery.
When alternate pulses are generated at pins 10 and 11 of the IC 4047 they drive the Mosfets.
These activated Mosfets play a crucial role in the working of the circuit.
The activated Mosfets drive the secondary winding of the transformer.
This action leads alternate magnetic fields in the transformers core.
As a result of the induced magnetic fields a high alternate voltage is produced at the transformers output reaching around 220 Volts.
Overall the IC 4047 generates alternate pulses which is applied to the Mosfets drive, the transformers secondary winding inducing magnetic fields that in turn produce the desired 220V AC output.
Controlling the output voltage becomes simple by the adjustable parts like the capacitor and potentiometer.
This circuit functions as an easy but effective way of transforming DC power from a battery into AC power that is used to power many kinds of devices and appliances.
Formulas:
Below are some important formula to follow while designing a circuit like this:
Transformer Turns Ratio:
The output voltage is measured by the transformers turns ratio.
The ratio of the input voltage (Vi) to the output voltage (Vo) is equal to the ratio of secondary turns (Ns) to primary turns (Np).
The following formula is applied:
Ns / Np = Vo / Vi
here,
- Ns is the number of turns in the transformers secondary coil which creates the greater voltage.
- Np is the number of turns in the transformers main coil which takes in the lower input voltage.
- Vo is the transformers output voltage which is usually a higher AC voltage.
- Vi is the transformers input voltage which is usually a lower DC value.
A transformer operates on the essential principles of electromagnetic induction.
A magnetic field is generated by the primary coils current flow.
The secondary coil subsequently begins to conduct due to this magnetic field.
Each coils rotation count has an impact on the magnetic fields strength and the induced voltage
How the formula works:
More Turns More Voltage:
If the secondary coil (Ns) has more turns than the primary coil (Np) the output voltage (Vo) will be higher than the input voltage (Vi).
This is due to a higher induced voltage generated when the secondary coils increased number of turns increases the magnetic field.
Fewer Turns Less Voltage:
However if the secondary coil has fewer turns than the primary coil the output voltage will be lower than the input voltage.
The secondary coils voltage decreases as a result of a weaker magnetic field caused by fewer turns.
Note:
Hence how much the voltage is stepped up or stepped down by the transformer depends on the ratio of Ns to Np.
Using this formula one can get the anticipated output voltage depending on the input voltage and the number of turns in the transformer coils.
How to Build:
The following steps are used in building a basic 100 watt inverter circuit using an IC 4047.
- Connect the 12V DC batteries positive terminal to the circuit and the negative terminal to the Mosfets source pins.
- The 4047 IC should be inserted into the circuit after being placed in an IC socket.
- Ensure the correct position.
- Connect the potentiometer VR1 across pins 6 and 7 of the 4047 IC.
- Wire a capacitor C1 between pin 6 and the ground negative of the circuit.
- Join the drain pins of the Mosfets to the secondary winding of the transformer.
- The Mosfets source pins must be connected to the batteries negative terminal.
- Primary winding of the transformer pin is connected to the output pins of the 4047 IC pins 10 and 11.
- Secondary winding of the transformer pin is connected to the drain pins of the Mosfets.
- Add resistors and other circuit parts based on the circuit design.
- Keeping the connections clean and avoiding short circuits arrange the parts on the PCB or breadboard.
- To ensure a strong and secure connection, carefully solder links.
- Using the 12V DC battery turn on the circuit.
- Measure the output voltage across the secondary winding of the transformer using a multimeter.
Adjustments:
- To change the pulse frequency adjust the potentiometer and see how it impacts the output voltage.
- To get the desired 220V AC output fine-tune the circuit.
Safety:
- Remember to follow safety precautions when working with electronic circuits and go through the datasheets for the 4047 IC and other components for more information.
- Also double check the connections to ensure accuracy before applying power to the circuit.
Conclusion:
Inverters as simple yet powerful electronic devices bridge the gap between DC and AC power supplies.
The presented simple 100 watt inverter circuit using the 4047 IC shows an useful and cost effective solution.
Through understanding of the basics and attention to construction guidelines both hobbyists and designers can start creating their own inverters for various uses from small scale projects to larger power systems.