Sensor Project Essay I have decided to measure the temperature of a greenhouse using a thermistor in a potential divider circuit, and then when the temperature gets too cold, the relay will activate and turn on a heater. A thermistor is a temperature sensor in which its resistance will increase or decrease with temperature change depending on what type of resistor. An alternative for this experiment could have been measuring light levels in a greenhouse using an LDR. A light sensor in a green house could tell you when and where in the greenhouse the most intense sunlight is, which you could you use to aid your growing skills. I decided to design a temperature sensor for a greenhouse using a thermistor, as temperature can be critical in growing plants especially if it gets too hot or too cold. As my thermistor is an NTC this means that as temperature decreases its resistance increases, and when temperature increases its resistance decreases. Plan: Circuit Explanation The water is boiled until it reaches a temperature of just above 90i Celsius. The thermistor is inserted into the hot water and the voltage across it is measured for a temperature of 90i. The varying voltage across the thermistor is measured as the temperature falls at 10-degree intervals. The experiment is repeated and a second set of readings obtained. An average set of readings is obtained and a voltage-temperature conversion graph is plotted. Then test the sensor by attaching the amplifier and relay. Materials/Apparatus Needed: Thermometer, Thermistor, Beaker, Electric kettle, Power supply, Multimeter, Variable resistor, Amplifier, Relay, Leads. These pictures show me testing the thermistor (left), and testing the amplifier to see at what voltage it activates (right). Variables The volume of water used for this experiment was kept at 250cmi The experiment was completed over one day, and on the day, the temperature in the physics laboratory where the experiment took place was 19i C. Results Calculation of R1: I want my amplifier to activate at 10i C, for the heater to come on. The amplifier turns on at 1. 93V, as I have tested, and because the voltage is proportional to the resistance, I will work out which resister to use using the equation below. (At 10i C the thermistors resistance is 124. 8? )
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1/4/2020 0 Comments Thirteen Days Research Paper Example | Topics and Well Written Essays - 250 wordsThirteen Days - Research Paper Example He is facing world war 3 in the near future. They have to come up with a quick plan on how to stop the war heads from being operational. President Kennedy does not want to invade Cuba, though the chiefs of staff really think that invading Cuba would be the best solution at the moment. He says the same course of events led to the break out World War 1. This time the risks were high because nuclear weapons were involved. They settle on blockade as the first measure which technically is an act of war that would help remove the missiles from Cuba as well as avoid war. They agree not to call it a blockade but quarantine. This is where the US navy ships will stop any ships that enter Cuban water for inspection to make sure they are not carrying any lethal weapons into Cuba. Cuban ambassador to the US at first assures president Kennedy that there are weapons in Cuba but they are only for defensive but not offensive purposes, which the president sees as lies and sends US ambassador to the UN Mr. Aldai Stevenson to a council meeting where he roughs up the Cuban ambassador with questions to categorically state if whether there are nuclear weapons placed in Cuba by the Soviet Union or not. The ambassador avoids the questions and says that the American government was spreading malicious information to incite nations. Throughout the entire process president Kennedy is pressurized by the chairman of Joint Chiefs of Staffs, General Maxwell Taylor to hasten an invasion before the whole chance of removing the missiles from Cuba become impossible. The president does not wish to subject innocent American citizens to an act world war 3. But all the same information starts spreading fast across all the American states about the possibility of a world war 3 which drives a major panic to the people who now shop for food stuff and other things in plenty just case a war breaks
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