Basic Circuit Analysis

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PART II

• Basic Circuit Analysis

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CHAPTER THREE

• Ohms Law

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RELATIONSHIP OF CURRENT TO VOLTAGE

• A Direct Relationship
• Increase Voltage and Current will Increase
• Decrease Voltage and Current will Decrease
• Resistance held constant

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RELATIONSHIP OF CURRENT TO RESISTANCE

• Indirect Relationship
• Increase Resistance and Current will decrease
• Decrease Resistance and Current will increase
• Voltage held constant

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MATHEMATICAL RELATIONSHIP OF V, I, and R

• Formulated with three variables V, I, and R
• Relationship called Ohms Law
• Three forms exist

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THE CIRCUIT
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OHMS LAW EXAMPLES

• Voltage 25 V
• Resistance 25 ?
• I _____

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OHMS LAW EXAMPLES

• Voltage 15 V
• Resistance 1 k?
• I _______

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DIRECT AND INVERSE RELATIONSHIPS

• Inverse relationship

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DIRECT AND INVERSE RELATIONSHIPS

• Direct relationship

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OHMS LAW EXAMPLES

• Resistance 50 ?
• Current 2.5 A
• Voltage _______

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OHMS LAW EXAMPLES

• Resistance 10 k?
• Current 4 mA
• Voltage ______

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OHMS LAW EXAMPLES

• Current 15 mA
• Voltage 15 V
• Resistance _______

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OHMS LAW EXAMPLES

• Current 4 mA
• Voltage 60 V
• Resistance _______

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CURRENT FLOW NOTATIONS

• Electron Flow Flow is from () to ()
• Conventional Flow Flow is from () to ()
• Older notation

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CIRCUIT REPRESENTATION OF CURRENT FLOW
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AC CHARACTERISTICS
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AC CHARACTERISTICS
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AC CHARACTERISTICS
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WORK, ENERGY, AND POWER

• Work Expenditure of energy
• Work Force Distance
• Energy Ability to do work
• Energy Power Time
• Power Rate of energy usage
• Power Energy/Time

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POWER AND OHMS LAW

• Power Current x Voltage
• P (watts) I (amps) x V (voltage)
• I 25 mA, V 10 V
• P (2 mA) x (10 V) 250 mW

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RELATIONSHIPS

• Note that if Current in the last slide doubles,
  Power will also double.
• P IV (50 mA)(10 V) 500 mW

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EQUATION SUMMARY
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BASIC CIRCUIT EXAMPLES

• R 10 k?, I 10 mA, V _____
• V 100 V
• V 50 V, I 2 mA, R ______
• R 25 k?
• V 75 V, R 10 k?, I ______
• I 7.5 mA

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POWER CALCULATIONS

• V 100 V, I 2 mA, R _____, P _____
• R 50 k?, P 200 mW
• V 250 V, R 25 k?, I _____, P _____
• I 10 mA, P 2.5 W