Have two halves, both are different due to resistors, transformer winding turns etc. Therefore both halves doesn’t conduct at the same time. Assume that the upper half transistors conduct first and get their biasing voltage through the lower half winding of the transformer via R2. When they saturate and conduct fully, the entire battery voltage is pulled through their collectors to the ground.

1. Topic of presentation:
Inverters
Group members:
1. Muhammad Farrukh Iqbal
2. Sohail Murtaza
3. Irum Batool
4. Moin Pattal

2. Outline of presentation:-
• Definition.
• History of inverters.
• Inverters working principal.
• Types of inverters.
• Application of inverters.
• Uses of inverter in textile.
• things in place of inverter.
• Future work with inverters.

3. Basic definition:
“one that inverts or produce inversion”.
OR
“A device that converts direct current
to alternating current ”.

4. History of inverters:-
• Rotary converters or motor-generator sets used in late
nineteenth century.
• Vacuum tubes and gas filled tubes began to be used as
switches.

5. How inverter woks:
•DC power is connected to transformer through the
center tap.
•A switch is rapidly switched back and forth to allow
current to flow back to the DC source.
•Alternation of current in the primary winding
produces alternating current (AC) in the secondary
circuit.

7. Inverter classification:
inverters are classified
by their ac output waveform.
1. Square wave
2. Modified square wave
3. True sine wave

9. True sine wave inverter:
 Provide better power as compared to the
modified sine wave inverters for homes.
 Best inverters employed for power
sensitive applications.
A bit expensive and cannot be afforded by the
common man.

10. Solar inverter:
•Energy efficient because do not require a
separate source for generation.
•Energy collected during daytime and used at
time of need after conversion.
• They are easy to install.

11. Applications of inverter:
A large application of inverter is
In textile industry.
 In circular knitting machine (circular loom).
In the aerospace and airline industries.
 In electroshock weapons.
 In uninterruptible power supply.

12. circular knitting machine:-
(circular loom)
• There is a mature control
system for knitting
machine.
• Basically the system is
using Single-Chip
Microcomputer.
• It require high torque at
low frequency, and
frequency inverter help in
this process.

13. Operation of knitting machine:-
• Its only need to control the start and stop
terminals, frequency setting using analog or
multi-range frequency setting.
• It requires frequency inverter that can
provide large torque at low frequency, because
weaving load is heavy, and requiring the quick
response for operation.
• Starting frequency can broke the needle.
• It require smooth path to stop the machine.

14. In uninterruptible power supply:
 use batteries and inverter when supply is not
available.
 When main power is restored, a rectifier supplies DC
power to recharge the batteries.

15. What can be used in place of inverter?
There are many devices that can be used
rather than inverters.
• power boss
• VFD(variable frequency drive)

16. Power boss:
• Provide us fixed frequency
• Variable voltage
VFD(variable frequency drive):
it is used to control AC motor
speed and torque by varying motor
input frequency and voltage.

17. Project:-
Circuit:-

18. Components:-
 R1, R2= 100 OHMS.
 R3, R4= 15 OHMS.
 T1, T2 = 2N3055 POWER TRANSISTORS.
 TRANSFORMER= 12- 0- 12 VOLTS / 8 AMPS.
 AUTOMOBILE BATTERY= 12 VOLTS/ 32AH

19. Procedure:-
• Firstly connect transistors tightly.
• Connect the resistances across the transistors
according to the circuit.
• Attach battery.
• Connect to the transformer.
• Get output.
• Attach a bulb.

20. Working:-
• Have two halves, both are different due to
resistors, transformer winding turns etc.
• Therefore both halves doesn’t conduct at the
same time.
• Assume that the upper half transistors conduct
first and get their biasing voltage through the
lower half winding of the transformer via R2.
• When they saturate and conduct fully, the entire
battery voltage is pulled through their collectors
to the ground.

21. They absorb any voltage through R2 to their
base and they immediately stop conducting.
Gives an opportunity for the lower transistors
to conduct and the cycle repeats.
Circuit thus starts to oscillate.
Base Emitter resistors help to fix a base biasing
reference level.