WEEK 5

WEEK 5

Activity : 

Doing some research on the operation and components of Marx Generator

Objective : 

• To study on basic operation of Marx Generator
• to study about the components in Marx Generator.

contents:

Principle Operation Of Marx Generator

The circuit generates a high-voltage pulse by charging a number of capacitors in parallel, then suddenly connecting them in series. See the circuit above. 

At first, n capacitors (C) are charged in parallel to a voltage V by a high voltage DC power supply through the resistors (R_C). The spark gapsused as switches have the voltage V across them, but the gaps have a breakdown voltage greater than V, so they all behave as open circuits while the capacitors charge. The last gap isolates the output of the generator from the load; without that gap, the load would prevent the capacitors from charging. To create the output pulse, the first spark gap is caused to break down (triggered); the breakdown effectively shorts the gap, placing the first two capacitors in series, applying a voltage of about 2V across the second spark gap.^[2] Consequently, the second gap breaks down to add the third capacitor to the "stack", and the process continues to sequentially break down all of the gaps. The last gap connects the output of the series "stack" of capacitors to the load. Ideally, the output voltage will be nV, the number of capacitors times the charging voltage, but in practice the value is less. Note that none of the charging resistors R_c are subjected to more than the charging voltage even when the capacitors have been erected. The charge available is limited to the charge on the capacitors, so the output is a brief pulse as the capacitors discharge through the load (and charging resistors). At some point, the spark gaps stop conducting and the high voltage supply begins charging the capacitors again.

The principle of multiplying voltage by charging capacitors in parallel and discharging them in series is also used in the voltage multiplier circuit, used to produce high voltages for laser printers and cathode ray tubetelevisions, which has similarities to this circuit. The difference is that the voltage multiplier is powered with alternating current, and produces a steady DC output voltage, while the Marx generator produces a pulse.

Conclusion

For this week, I have learn the basic operation of Marx Generator and the components that should be used in my project. A lot of information regarding Marx Generator that I have to synthesize in making a good Marx Generator.