WEEK 2: DESIGN AND CONSTRUCT PROTECTION CIRCUIT

Objectives: 

• To Gain Knowledge about the most effective protection circuit and component.
• To Compare between other protection circuit.
• To Design and construct a suitable protection circuit.

Content / Procedure: 

• Make a research about suitable circuit for protection inverter, relay and so on.
• Make an analysis for Basic high voltage protection circuit
• Do an analysis and calculation to determine circuit performance.
• Make sure a suitable circuit to begin circuit developing.

Result and Analysis:

• The safety for main circuit design will be care by construct a protection circuit.
• I'm proposed a 3 stage protection circuit to make sure a higher current of electricity can't damage a circuit component.
• The analysis of protection circuit for stage 1 ( FUSE ):

Input current = Apparent power/input voltage

50/12 = 4.16AA

20% from value = [(20/100) × 4.16] + 4.16

                         = 4.9A (suitable fuse is a 5A)

Use 5A because it acts to prevent a loss load ( previously, i'm try a common 3.15 A but it is not suitable because blow cause by a high current. 

• The analysis of protection circuit for stage 2 ( ZENER DIODE ):

Zener Diode (11V), if 12V input

12V-11V = 1V : 1V will turn on the base of D1858, then relay will turn on

Zener Diode (15V), if 16V input

16V-15V=1V : 1V will turn off the base of D1858,then relay will turn off.

The moment relay connected, it will supply 12 V to whole circuit. If the relay received 11 V - 14 V, it will be on and functional and it happen otherwise when the circuit received below than 11 V and more than 15 V.

• The analysis of protection circuit for stage 3 ( WHITE RESISTOR ):

R = (1/R1 + 1/R2)^-1

= (1/0.33 + 1/0.33)^-1

= (6.06)^-1

= 0.16

P = I2R

10 = (I2) R

10W = (I2) (0.16)

I = 7.9 A (this two resistor can withstand 8A current)

Conclusions

• I'm sure that this circuit is suitable to be use in my final project.
• All the component's must be construct properly in order to protect main circuit.
• This 3 Stage protection circuit is necessary to make a reliable an efficient circuit.

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Kenali Abdul Syafiq :

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