If one bulb burns in electric garlands, all other bulbs keep working. Why? How it works?

Combination of resistors

өткізгіштерді тізбектей жəне параллель жалғауда тізбек бөлігі үшін Ом заңын қолданып, электр тізбектеріне есептеулер жүргізу You will design complex electric circuits (that have series and parallel combination of resistors) by using Ohms law. Мақсат

Series connection Equivalent resistance is a single resistance that can be replaced instead of several.

Example What is the equivalent resistance of the circuit shown in the figure? Calculate the current in a circuit and voltage in every resistor. V = 1.5 V.

Parallel connection Equivalent resistance is a single resistance that can be replaced instead of several.

Example Two 10 ohm resistors are connected in parallel to a 1.5 V cell. a) Draw a circuit showing how they are connected. b) Find the current on each resistor. c) Find the current in the main arm. d) Calculate the equivalent resistance.

Example A 3 ohms and a 6 ohms resistor are connected in series to a 3 V battery. 1) Draw a circuit showing how they are connected. 2) Calculate the main current and the current in each branch.

Series vs parallel connection It is both easier and cheaper to construct a series circuit than a parallel circuit. In series circuit the current must flow through one element to reach the next one. Parallel circuits are more complicated and expensive than series circuits. In a parallel circuit each element is directly connected to the power source.

Complex combinations of resistors A circuit which has both a series and a parallel combination of resistors is called a complex circuit

Example What is the equivalent resistance of the circuit given in the figure? What is the current in the main arm.

Exercise What is the equivalent resistance of the circuit given in the figure? What is the current in the main arm. A=1 Ω; B=2 Ω; C=3 Ω ;D=4 Ω; E = 5 Ω;

Exercise What is the equivalent resistance of the circuit given in the figure? What is the current in the main arm. A=1 Ω; B=2 Ω; C=3 Ω ;D=4 Ω; E = 5 Ω;

Exercise What is the equivalent resistance of the circuit given in the figure? What is the current in the main arm. A=1 Ω; B=2 Ω; C=3 Ω ;D=4 Ω; E = 5 Ω;

Exercise What is the equivalent resistance of the circuit given in the figure? What is the current in the main arm. A=1 Ω; B=2 Ω; C=3 Ω ;D=4 Ω; E = 5 Ω;

What is a short circuit?(короткое замыкание) Current choose the easiest way to flow like water. The first lamp is short circuit and almost all current flow through this wire.

What is a short circuit?(короткое замыкание) Equivalent resistance of a parallel connection of wire and resistor is zero

Combination – қосылу / соединение Series – тізбектей / последовательный Parallel – параллель / параллельный To separate – айыру / отделять

Home Work (for practice) 1. What is the equivalent resistance between K and M. 2. Calculate the currents in the circuit. 4. What is the current I in the circuit? 3. A student wants to measure the resistance of a resistor. Which circuit diagram should the student use?