Daily Sprint START What is a capacitor? Draw its symbol. Draw a circuit diagram for a camera flash. What else could a capacitor be used for?

MSA Prep Solve: x = 4 y = 2 3x +4y +x2 - xy

Conclusion Questions 1.    Describe something other than the examples you’ve been given that you believe uses a capacitor and its function in the device. -

Conclusion Questions 2.    What do capacitors have to do with the dangers of older television sets? - Older TV’s used large capacitors to operate. Those capacitors held enough charge to seriously injure someone if they touched it. The charge will remain in those capacitors long after the TV is out of use.

Transistors Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Transistors

Transistors Transistors Parts of the Transistor The First Transistor Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Transistors Transistors Parts of the Transistor The First Transistor Transistors as Amplifiers Transistors as Switches Night Light Circuit This presentation is intended to be used with Activity 6.2.6 Transistors

Symbol for Circuit Diagrams Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Transistors Transistor: A small electronic device used in a circuit as an amplifier or switch. Symbol for Circuit Diagrams

Parts of the Transistor Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Parts of the Transistor BASE EMITTER COLLECTOR The small base current controls the larger collector current.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics The First Transistor Considered by some to be the greatest invention of the 20th century Invented at Bell Laboratories in 1947 It is a crucial component in almost all modern electronic devices Engineers are working toward making them smaller so that more can be placed on computer chips. Many today are already smaller than a human hair. Replica

Transistors as Amplifiers Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Transistors as Amplifiers Small load (input) Large load (output)

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics

Transistors as Switches Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Transistors as Switches Large Current Load Small Current Load Build the circuit as shown. When the switch is closed, you should notice that the LED in the circuit connected to the base is very dim. But the other LED that is controlled is much brighter. A small current amount switching on a larger current Students may be able to build the following circuit without viewing the physical image.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Night Light Circuit Challenge: Create a system with a light that comes on when it is dark, similar to a street light. In the following circuit, will the LED be bright at day or night? The LED will be bright during the day because brightness causes the photoresistor’s resistance to decrease. When the resistance of the circuit decreases, more current can flow to the LED.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Night Light Circuit In your engineering notebook, sketch the circuit shown below. Current will always take the path of least resistance. Use a highlighter to trace the path that current will take from the source. Does current reach the base of the transistor? Will current be able to reach the light? The resistors in the circuit are added to protect the LED and the base of the transistor. Current cannot reach the base of the transistor in order to cause current to flow through the transistor to activate the LED.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Night Light Circuit In your engineering notebook, sketch the circuit shown below. In brightness the photoresistor’s resistance is low. Use a highlighter to trace the path when there is very little resistance from the photoresistor. Does voltage reach the base of the transistor? Will voltage be able to reach the light? Current does not reach the base of the transistor, which does not allow current to flow to the LED.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Night Light Circuit In your engineering notebook, sketch the circuit shown below. In darkness the photoresistor’s resistance is high. Use a highlighter to trace the path when there is a large amount of resistance from the photoresistor. Trace the secondary path of resistance. Is the voltage high enough to activate the base circuit of the transistor? Will current be able to reach the light? Once the resistance of the photoresistor becomes high enough, it will bypass that path, go through the base, switch on the transistor’s path, and light the LED.

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Night Light Circuit Build the circuit as shown to test using actual components using Snap Circuits® spring sockets. If the circuit does not work as expected, troubleshoot using the flow chart provided in Activity 6.2.6 Transistors (omit the suggestion to check solder connections).

Transistors Gateway To Technology Unit 6 – Lesson 6.2 – Electronics Image Resources Microsoft, Inc. (2009). Clip Art. Retrieved January 27, 2009, from http://office.microsoft.com/en-us/clipart/default.aspx