Do you want to know more about this simple inverter circuit? Capable of outputting 50 watts total with just a few components.
This is an IC 555 inverter circuit. Because of using the 555 TIMER and MOSFET as main. I experiment with it to work well.
When using a 12V battery as a source, it will output 220V AC 50Hz
The Basic Principle of the Circuit
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Initially, the DC voltage from the battery goes into a square wave oscillator circuit (50Hz Oscillator), producing 50Hz AC voltage. But the current is way too low.
Recommended: How does NE555 timer circuit work
What to do to raise the current?
In this case, power switching (A-B switch) such as power transistors or MOSFETs are one good choice.
But the AC voltage is still at 12V? The Transformer inductance will raise the voltage into
220V AC 50Hz, ready to be applied to a load.
How 555 inverter circuit works
The circuit below is a complete circuit diagram of this project. I use the IC-NE555 timer is a square wave frequency generator output of 50Hz.
The frequency is determined by the R2 Resistor and C1 Capacitor.
555’s Output Frequency Calculation
If your R2 is 150K, then the output is 47Hz. You may add a potentiometer to fine-tune it to 50Hz later down the line.
MF4Me said: By calculation (results will vary depending on the component tolerances) a good combo of common parts would be:
- 0.2 μF (2 x 0.1 in parallel)
- 100Ω for R1
- 72K (39K and 33K in series) for R2.
The calculation result is 50.069 Hz with a 50.03 duty cycle. That is smart accuracy. If its tolerances are low.
What is more?
We use N-type MOSFET IRF540 (Q2, Q3) to drive a transformer coil (primary winding).
The output current at Pin 3 of IC1 will flow in two ways.
- First, through R3 to a gate of Q2.
- Second, flows to Q1-transistor BC549 as inverter logic form to reverse signal difference first ways.
Next, the current flows to the gate of Q3 to also drive the transformer.
It inducted low voltage to high voltage, from about 220V to 250V depending on the battery (12V to 14.4V).
The circuit diagram of the MOSFET Inverter
For the transformer, I use 2A of current, if a 12V input voltage. It causes the output power to be more than 100 watts.
Here are a few related posts you may find helpful, too:
- 1.5V to 220V Simple Inverter circuit
- 500W MOSFET Inverter
- How to make simple inverter circuit diagram within 5 minutes
Why use MOSFET?
In the circuit, we use IRF540 MOSFET. There are many reasons to use them.
- It is easy to use. They do not need the pre-drive transistor in Darlington to be the same as normal transistors, such as TIP41, 2SC1061, etc.
- It can drive a high current load, 27A max. While the TIP41 transistor can only drive a 4A load.
- It is inexpensive, just 0.8USD per pc.
- The body is similar to a TIP41 transistor, so it is easy to mount to a heatsink.
- They can be mounted to a smaller heatsink than a transistor, because of their low heat output.
The component list
IC1: NE555 timer IC = 1 pcs.
Q1: BC549-NPN 40V 0.5A transistors = 1 pcs.
Q2, Q3: IRF540-N CHANNEL POWER MOSFET, 100V, 27A, TO-220; 2 pcs.
C1,C2: 0.1uF 100V mylar capacitors = 2 pcs.
R1: 4.7K = 1 pcs.
R2: 120K = 1 pcs.
R3,R4: 1K = 2 pcs.
R5: 5.6K = 1 pcs.
T1: 2A 12V CT 12V transformer = 1 pcs.
Building and testing of 555 inverter circuit using MOSFET
In this project, I assemble components on a universal PCB board. As Figure 2, while operating it will get a little hot. So be sure to use enough heatsink.
Then, check the circuit for errors. Please watch the video below.
When checking all no error
We will test it with a 100 watts lamp at the output, with a 12V battery as a source. You will see that the lamp glows. But the battery voltage is slightly low, so the AC voltage output is 190V.
After that, We check waveform is a square wave as shown on the scope.
Some people wonder about something. I will share it with you.
I put the 470uF 50V electrolytic capacitors to filter the current.
It does not need if you use a 12V 10Ah battery. Because it is a stable power current source.
Ideally, if you need full 100 watts output. You need to use 8A transformer. Because of input watts = output watts = 100 watts.
When the primary coil voltage of the transformer is 12V at 100 watts.
The output current input = 100W/12V = 8A (approximately)
If it not working
I feel bad if you have built this project and it does not work.
First, you need to review the pin of the IC, resistors, and
capacitors. And importantly is how you connect the MOSFET.
Second, should do not connect the power cord to the transformer and MOSFET.
Third, check the 555 timers working, and frequency generators at pin 3 first. You may use a voltmeter to measure a voltage across pin 3 and the ground. You use surely oscilloscope to watch waveform.
Check out these related articles, too:
- 200W Power Inverter Circuit
- 100w Inverter circuit 12V to 220V using Transistor
- Simple inverter circuit using 6 transistors
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