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# dc to ac circuit

Inverters are typically required at places wherever it’s impracticable to urge AC offer from the Mains. Associate in Nursing electrical converter circuit is employed to convert the DC power to AC power. Inverters may be of 2 sorts True/pure undulation inverters and similar or changed inverters. These true /pure undulation inverters are pricey ,while changed or similar inverters are cheap.
These changed inverters turn out a sq. wave and these don’t seem to be accustomed power delicate electronic equipments . Here, a straightforward voltage driven electrical converter circuit victimization power transistors as shift devices is build, that converts 12V DC signal to single part 220V AC.
Principle Behind this Circuit
The basic plan behind each electrical converter circuit is to supply oscillations victimization the given DC and apply these oscillations across the first of the electrical device by amplifying this. This primary voltage is then stepped up to a better voltage relying upon the amount of turns in primary and secondary coils.
A 12V DC to 220 V AC convertor may also be designed victimization easy transistors. It may be accustomed power lamps up to 35W however can be created to drive a lot of powerful hundreds by adding more MOSFETS.
The electrical converter enforced during this circuit may be a sq. wave inverter and works with devices that don’t need pure undulation AC.
Working
The circuit may be divided into 3 parts: generator, electronic equipment and electrical device. A 50Hz generator is needed because the frequency of AC offer is 50Hz. This can be achieved by constructing Associate in Nursing Astable multivibrator that produces a sq. wave at 50Hz. within the circuit, R1, R2, R3, R4, C1, C2, T2 and T3 kind the generator.
Each junction transistor produces inverting sq. waves. The values of R1, R2 and C1 (R4, R3 and C2 are identical) can decide the frequency. The formula for the frequency of sq. wave generated by the astable multivibrator is
F = 1/(1.38*R2*C1)
The inverting signals from the generator are amplified by the facility MOSFETS T1 and T4. These amplified signals are given to the transformer with its center faucet connected to 12V DC.
The turns quantitative relation of the electrical device should be 1:19 so as to convert 12V to 220V. The electrical device combines each the inverting signals to get a 220V alternating sq. wave output.
By employing a 24V battery, hundreds up to 85W may be high-powered, however the look is inefficient. so as to extend the capability of the electrical converter, the amount of MOSFETS should be increased .
To design a a hundred watt electrical converter scan easy 100 Watt inverter
12v DC to 220v AC convertor Circuit victimization Astable Multivibrator
Inverter circuits will either use thyristors as shift devices or transistors. commonly for low and medium power applications, power transistors are used. the rationale for victimization power junction transistor is that they have terribly low output resistivity, permitting most current to flow at the output.
One of the necessary applications of a junction transistor is in shift. For this application, the junction transistor is biased in saturation and cut-off region.
When the junction transistor is biased in saturation region, each the collector electrode and collector base junctions are forward biased. Here the collector electrode voltage is minimum and collector current is most.
Another necessary side of this circuit is that the generator. a vital use of 555 Timer IC is in its use as Associate in Nursing astable multivibrator.
An astable multivibrator produces Associate in Nursing signal that switches between the 2 states and thus may be used as an generator. The frequency of oscillation is set by the values of capacitance and resistors.
Circuit style clarification
Oscillator Design:An astable multivibrator may be used as Associate in Nursing generator. Here Associate in Nursing astable multivibrator victimization 555 timer is intended. We know, frequency of oscillations for a 555 timer in astable mode is given by:
f = 1.44/(R1+2*R2)*C
where R1 is that the resistance between discharge pin and Vcc, R2 is that the resistance between discharge pin and threshold pin and C is capacitance between threshold pin and ground. conjointly the duty cycle of the signal is given by:
D = (R1+R2)/(R1+2*R2)
Since our demand is f =50Hz and D = five hundredth and assumptive C to be zero.1uF, we are able to calculate the values of R1 and R2 to be 10K and 140K Ohms severally. Here we tend to like employing a 150K potentiometer to fine tune the signal.
Also a ceramic capacitance of zero.01uF is employed between the management pin and ground. Switching Circuit Design:Our main aim is to develop Associate in Nursing AC signal of 220V. this needs use of high power transistors to permit the flow of most quantity of current to the load. For this reason we tend to use an influence junction transistor TIP41 with a most collector current of 6A, wherever the bottom current is given by the collector current divided by the DC current gain. this provides a bias current of regarding zero.4A *10, i.e.4A. but since this current is over the utmost base current of the junction transistor, we tend to like a worth but the utmost base current. allow us to assume the bias current to be 1A. The bias resistance is then given by
Rb = (Vcc – VBE(ON))/Ibias
For each junction transistor, the VBE(ON) is regarding 2V. therefore metal for every is calculated to be ten Ohms. Since the diodes are used for biasing, the forward dip across the diodes ought to be capable the forward voltage drops across the transistors. For this reason, diodes 1N4007 are used.
The design issues for each the PNP and NPN transistors are same. we tend to are employing a PNP power junction transistor TIP42.
Output Load Design: Since the output from the shift circuit may be a pulse dimension modulated output, it’d contain harmonic frequencies aside from the elemental AC frequency. For this reason, Associate in Nursing solution capacitance must be accustomed enable solely the elemental frequency to submit to it. Here we tend to use Associate in Nursing solution capacitance of 2200uF, massive enough to filter the harmonics. Since it’s needed to urge 220V output, it’s most well-liked to use a maximize electrical device. Here a 12V/220V maximize electrical device is employed.
12v DC to 220v AC convertor Circuit Operation
When this device is high-powered victimization the 12V battery, the 555 timer connected in astable mode produces sq. wave signal of 50Hz frequency.
When the output is at logic high level, diode D2 can conduct and also the current will submit to diode D1, R3 to the bottom of junction transistor Q1.
Thus junction transistor Q1 are switched on. once the output is at logic low level, diode D1 can conduct and current will flow via and D1 and R4 to the bottom of Q2, inflicting it to be switched on.
This allows the DC voltage to be made across the first of the electrical device at alternate intervals. The capacitance ensures that the frequency of the signal is at the specified harmonic.
This 12V AC signal across the first of the electrical device is then stepped up to 220V AC signal across the transformer secondary.
Applications of 12v DC to 220v AC convertor Circuit
This circuit may be employed in cars and alternative vehicles to charge tiny batteries.
This circuit may be accustomed drive low power AC motors
It may be employed in solar energy system.
Limitations
Since 555 Timer is employed, the output could slightly vary round the needed duty cycle of fifty, i.e. actual five hundredth duty cycle signal is tough to attain.
Use of transistors reduces the potency of the circuit.
Use of shift transistors has the likelihood of inflicting cross over distortion within the signal. but this limitation has been reduced to some extent by the utilization of biasing diodes.
Note
Instead of 555 timer one will use any astable multivibrator. for instance this circuits may also be build victimization 4047 astable multivibrator,whose output current is amplified and applied to the electrical device.