Page 15 - The Basics IA by ETron Circuit Labs

Photocells are used to vary the amount of resistance in many types of electronic devices. For example, they are used to automatically turn on lights when it gets dark.Procedure:Assemble the circuit and connect a 9-volt battery to the Battery Snap and observe the brightness of the LED. Now, cover the Photocell with your finger to keep light from getting to it, Notice that the LED gets dimmer when you cover the photocell.Observations:By doing this experiment you have seen that the Photocell will vary the brightness of the LED depending on how much light is hitting the surface of the Photocell.Conclusion:You can conclude that the function of the Photocell is to vary the resistance in a circuit with light.Check Your Work Here a b c d e 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 a b c d e f g h i j 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 f g h i j Here’s What You’ll Need...PHOTOCELLR1hole 21d hole 22dLRIL = Light IntensityR = Resistance across Photocell I = Current across PhotocellWhen light increases, resistance decreases, and current increases and so the light gets brighterAnode CathodeLIGHT EMITTING DIODE (LED)LED 1Cathode (flat side)hole 21j hole 22jB1REDWIRESW1 = 21e & 21fBLACKred = hole 22a black = hole 22fSCAN HERE TO SEE MORE ONLINE1X3XLAB 7AnodeVisit us online at www.ETronCircuit.com for more exciting projectsDid you know...Photocells are used as timers to measure the speed of runners during a race.