Any circuit with sources and resistors can be
Any circuit with sources and resistors can be replaced by an equivalent circuit containing a single voltage source and a single resistor.
1. Break the part A-B There is no current through R 1 because above calculations are done in an open circuit condition between A and B. Therefore no voltage drop along this part.
2. Calculate voltage between A and B 3. Reomove all the sources and calculate Req The equivalent circuit is a voltage source with voltage Vth in series with a resistance Req.
Any Thevenin equivalent circuit can be replaced by a current source in parallel with a resistor.
1. Connect the part A-B Current starts to flow between A and B. 2. Calculate the current
3. Reomove all the sources and calculate Req the equivalent circuit is a 3. 75 m. A current source in parallel with a 2 kΩ resistor.
Loading Effect Smaller the resistance Rs is, more voltage is transferred from a source to a load
Loading Effect Bigger the resistance Rs is, more current is transferred from a source to a load
Power Limiting In Thevenin Equivalent Circuit RL VL IL 1Ω 1 V 1 A 10Ω 10 V 1 A 1 kΩ 10 V 10 m. A 100 kΩ 10 V 100µA Maximun Power Consumption : 10 W Rated Voltage : 10 V => Rated Maximun Current : 1 A As a load resistance is 1Ω, voltage of the above circuit is supposed to be 10 V and current 10 A and power consumption 100 W. However, the power consumption is out of the maximum level then this circuit cannot work properly. It is called an overload. Therefore, to maintain the maximum power consumption, the current is supposed to be 1 A and the voltage 1 V in accordance with Ohm’s law.
12 V I 10 1, 00000001 8 0, 100000001 6 V(V) 0, 0100000001 I(A) 4 0, 00100000001 2 0, 000100000001 0 1, 00000001 E-05 1Ω 10Ω 1 kΩ 100 kΩ In accordance with the load resistance, voltage and current change. As the resistance is smaller than 10 Ω, the circuit is on the overload.
Power Limiting In Norton Equivalent Circuit RL IL VL 1Ω 10 m. A 0. 01 V 100Ω 10 m. A 1 V 10 kΩ 10 m. A 100 V 100 kΩ 1 m. A 100 V Maximun Power Consumption : 1 W Rated Current : 10 m. A => Rated Maximun Voltage : 100 V As a load resistance is 100 kΩ, current of the above circuit is supposed to be 10 m. A and voltage 1000 V and power consumption 10 W. However, the power consumption is out of the maximum level then this circuit cannot work properly. It is called an overload. Therefore, to maintain the maximum power consumption, the voltage is supposed to be 100 V and the current 1 m. A in accordance with Ohm’s law.
I In accordance with the load resistance, voltage and current change. As the resistance is bigger than 10 kΩ, the circuit is on the overload.
õ The rated voltage in Korea is 220 V. õ We nowadays use fixed voltage in parallel with electric appliances. õ Therefore, overload is caused by excessive current. Overload might happen if we put many plugs of electric appliances in the only one outlet.
õ Each of electric appliances has individual power consumption. For instance, we have an american electric appliance(rated voltage is 120 V in America) that power consumption is 120 W. It allows current to flow up to 1 A and its resistance is 120Ω. Thus, if we plug it in korea, the current 1. 9 A flows through the appliance then the appliance is damaged due to overload.
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