Our electronics and appliances usually need AC power to work, even if the original source of power is DC like a battery.
This is why things like phone chargers and UPS systems battery backups need a special part called an inverter.
An inverter changes DC power to AC power.
This article shows you how to build a basic 100 watt inverter circuit using a common chip called the IC 4047.
It will explain how the inverter works and how to build it yourself.
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 | |
| Other | Transformer as per diagram | 1 |
| Power Source | 12V Battery | 1 |
The simple 100 watt inverter circuit utilizing 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.
Simultaneously, the source pins of the Mosfets are linked 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 functioning of the circuit.
The activated Mosfets drive the secondary winding of the transformer.
This action induces alternate magnetic fields in the transformer’s core.
As a result of the induced magnetic fields, a high alternate voltage is produced at the transformers output reaching around 220 Volts.
To summarize, the IC 4047 generates alternate pulses which, when applied to the Mosfets drive the transformers secondary winding inducing magnetic fields that in turn produce the desired 220V AC output.
The adjustable components such as the potentiometer and capacitor allow for flexibility in controlling the output voltage.
This circuit serves as a basic yet effective mechanism for converting DC power from a battery into AC power suitable for powering various appliances and systems.
Formulas:
Below are some important formula to consider when designing a circuit like this:
Transformer Turns Ratio: The output voltage is determined 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 can be applied:
Ns / Np = Vo / Vi
here,
- Ns: This is the number of turns in the transformers secondary coil, which produces the greater voltage.
- Np: This is the number of turns in the transformers main coil, which is the one that takes in the lower input voltage.
- Vo: This is the transformers output voltage, which is usually a higher AC voltage.
- Vi: This is the transformers input voltage, which is usually a lower DC value.
A transformer operates on the fundamental tenet of electromagnetic induction.
A magnetic field is produced 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: The output voltage (Vo) will be greater than the input voltage (Vi) if the secondary coil (Ns) has more turns than the main coil (Np).
This is because a higher induced voltage is produced when the magnetic field is strengthened by the secondary coils increased number of turns.
Fewer Turns, Less Voltage: On the other hand, the output voltage will be lower than the input voltage if the secondary coil has less turns than the primary coil.
Less turns result in a weaker magnetic field, which lowers the secondary coils voltage.
Note:
Thus, how much the voltage is ‘stepped up’ or ‘stepped down’ by the transformer depends on the ratio of Ns to Np.
Using this formula, you may get the anticipated output voltage depending on the input voltage and the number of turns in the transformer coils.
Construction:
Building simple 100 watt inverter circuit using IC 4047 involves several steps.
- Connect the positive terminal of the 12V DC battery to the circuit and the negative terminal to the source pins of the Mosfets.
- Place the 4047 IC into an IC socket and insert it into the circuit.
- Ensure the correct orientation.
- Connect the potentiometer VR1 across pins 6 and 7 of the 4047 IC.
- Connect a capacitor C1 between pin 6 and the ground negative of the circuit.
- Connect the drain pins of the Mosfets to the secondary winding of the transformer.
- Connect the source pins of the Mosfets to the negative terminal of the battery.
- Connect the primary winding of the transformer to the output pins of the 4047 IC pins 10 and 11.
- Connect the secondary winding of the transformer to the drain pins of the Mosfets.
- Add resistors or other components based on the circuit design or specific requirements.
- Arrange the components on the PCB or breadboard keeping the connections neat and avoiding short circuits.
- Solder the connections carefully ensuring a strong and reliable joint.
- Power on the circuit using the 12V DC battery.
- Use a multimeter to measure the output voltage across the transformers secondary winding.
Adjustments:
- Adjust the potentiometer to vary the pulse frequency and observe the effect on the output voltage.
- Fine tune the circuit to achieve the desired 220V AC output.
Safety:
- Remember to follow safety precautions when working with electronic circuits, and consult the datasheets for the 4047 IC and other components for detailed specifications.
- Additionally, 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 utilizing the 4047 IC exemplifies an accessible and cost effective solution.
By understanding the principles and following construction details enthusiast and designers alike can embark on building their own inverters for various applications, from small scale projects to more extensive power systems.