You can read books at night under a light. Energy from AC main makes it happen. But if you do not have an AC voltage. Do You still use a light? You need to use a 100w Inverter circuit and battery.
Also, If you are outside a house, no electricity. You cannot use a lamp with a 12V battery.
This circuit is a mini inverter circuit using power transistor 2N3055 as the main components without IC.
It is designed for you that need to use appliances outdoor or no electricity. Someone use it in a car or the high mountain etc.
It can be converted 12VDC to 220VAC. The maximum output power about 100 watts. It is suitable for normal lighting (all home lamps), also used for radio, LCD TV, Stereo.
Someone uses it for a small soldering iron to repair or build many projects outdoor home.
How 100W inverter circuit works
See the circuit diagram below
Figure 1, 100w Inverter circuit, 12V to 220VAC using transistors
This circuit will include five main sections as a block diagram.
1. Q1 and Q2 act as the frequency oscillator circuit.
2. Q3 and Q4 act as the frequency divider circuit
3. Q5 and Q6 act as the transistor driver circuit.
4. Q7 and Q8 act as the output power amplifier circuit.
5. T1 is a voltage converter to power a load.
Here is a step-by-step process.
First, both PNP transistors Q1, Q2 will be connected together as the astable multivibrator form. They will generate the output frequency of about 100 Hz at the collector lead of Q2.
This frequency is set by both resistors R1, R2, and two capacitors C1, C2. And there are both diodes D1, D2 to set only positive voltage through the emitter lead of Q1, Q2.
Then, this signal flows through to the frequency divider by two. It makes the frequency is reduced down to about 50Hz.
Why we don’t design the circuit to directly work at 50 Hz. Because generating the steady low frequency is too hard.
The output from the divider circuit is sent to the base of Q5, Q6. To increase current up to drive the output transistors Q7, Q8, then drive the transformer, finally to supply load.
1. Normally, use the 2-3A transformers for 20-30watt for the incandescent lamp. But use need 100watt use must use 8A transformer so expensive for me.
2. The primary coil of transformer use may use 9V CT 9V or 10V ct 10V or 12V ct 12V.
Which normal I use 12V ct 12V makes the output voltage about AC 220V (no load). But there is load voltage will reduce to AC190V
3.This circuit will has output as square wave form. So cannot use for inductor load.
4. This transformer, we may use secondary coil is the output voltage as you need, example we connects to the power amplifier that use AC 24 volts so we use AC 24V secondary coil etc.
How to builds
It is like all our projects. To begin with make the PCB or you can use the universal PCB. Then, assemble all part on PCB as Figure 2. Next check all for error. Check again and check again.
Then apply the 12V 10A battery to this circuit and use the voltmeter to measure AC voltage output. Next connects load to the circuit.
PCB layout and components layouts of the 100w Inverter circuit, 12V to 220V using Transistors
Parts you will need
Q1-Q4: BC557, 45V 100mA PNP Transistor
Q5, Q6: BD139, 80V 1.5A NPN Transistor
Q7, Q8: 2N3055, 100V, 15A, 115W, >2,5MHz NPN transistor
D1, D2, D3, D4: 1N4148, 75V 150mA Diodes
D5, D6: 1N4007, 1000V 1A Diodes
0.5W Resistors tolerance: 5%
R1, R4, R6, R7: 10K
R2, R3: 150K
R5, R6: 47K
R9, R12: 220 ohms
R10, R13: 560 ohms
R11, R14: 100K
R17, R18: 150 ohms
R15, R16: 10 ohms, 10W Resistors tolerance: 5%
C1,C2: 0.047uF 50V
C3,C4: 0.01uF 50V
C5: 1uF 50V
C6: 0.1uF 250VAC
C7: 0.1uF 50V
C8: 220uF 25V, Electrolytic capacitors
T1: 230V AC primary to 12V-0-12V,2-8A secondary transformer.
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