Introduction

12 VDC to 120 VAC Inverter

Juan Tello

Summary

Background How the circuit works?SimulationTestingApplicationsConclusion

The Circuit

Schematic using Simplorer

TWT

TWT1

TWT

TWT2

DIODE51

DIODE52

R1

R2

C1

C2

R3

R4

NPN51

NPN52

C3 R5

Simulation Output

Half Circuit R4 & C2

Just One Cycle

Half Circuit D1 & R1

One Cycle

Half Circuit VCE2 & TV1

One Cycle

Half Circuit One Cycle

Half Circuit Analysis

During Positive Cycle

D1 is closed

Q2 is open

C1 is discharging

T2-V1 is negative voltage

The Other Half Circuit

Simulation Summary

During Positive Cycle

Bottom Top

D1 is closed D2 is open

Q2 is open Q1 is closed

C1 is neg. C2 is zero

T2 is neg. T1 is Neg. Const.

Simulation Summary

During Negative Cycle

Top Bottom

D1 is closed D2 is open

Q2 is open Q1 is closed

C1 is neg. C2 is zero

T2 is neg. T1 is Neg. Const.

Real Circuit—Top View

Real Circuit—Bottom View

Transformer from a Microwave

Transformer and Circuit

Testing the circuit

Oscilloscope

Oscilloscope closed up

Measuring with a Voltmeter

Problems and Solutions

Capacitors of 68uF were replaced with 2-33uF and 1-2.2uF

Steel wire was used in the primary winding on transformer instead of copper wire

Frequency = 1.3kHz No solutionVp-p = 40V No solution

Application

Automobile

- TV’s

- DVD’s

- VCR’s

- Other household appliances

Conclusion

Advantages

- Low cost

- Easy to built

Disadvantages

- Reliability

- Efficiency

Conclusion (continuation)

Who makes this productFuture work

- Further investigation to solve present problems: frequency, output voltage, load variation