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ANSWER ONLY PART iii
Q1 An rocket motor is monitored by a thermocouple to ensure the rocket is not damaged by high temperatures, A system is required which will cut the motor if the event of the temperature reaching 1500°C, as exceeding this temperature could destroy it. In order to prevent the rocket engine being damaged by a sudden increase of temperature before the engine has time to cut out, the motor is also required to cut out if the rate of increase in temperature exceeds a specific preset value. The output from the analogue section is then fed into a digital circuit (5V = logical 1, OV = logical 0). This will produce a logical 0 trigger an alarm when either of the inputs are high, which will remain on until the alarm is reset. The system will be partially analogue and partially digital. i. Select a thermocouple from Table 1, justifying your selection. [2 marks] ii. Design a circuit to produce voltage outputs in the range OV to 10V for temperature. Include values, and derive the equation for the amplifier. State any limitations your choice presents. [20 marks] iii. Show how you would design a circuit to measure the rate of temperature increase. [10 marks] iv. Design additional components to produce a 5V signal when either of the conditions are met, and OV otherwise. [8 marks] V. Design the logic gate circuit you would need to trigger the alarm and keep it on until reset, explaining your rationale explain how it works. [10 marks] Table 1: Temperature Sensitivity Range[°C] [µV/°C] -270~1000 60.9 -210~1200 51.7 -270~1350 40.6 -270~400 40.6 -50~1750 6 Code Material E Chromel & Constantan J Iron & Constantan Chromel & Alumel Copper & Constantan Platinum & 87% Platinum/ Rhodium K T R 13%