ELECTROTECHNOLOGY 1100
ASSIGNMENT #5

1. An electric iron contains 1.1 Kg of water. It takes 12 minutes to raise the temperature of the water from 31°C to 78°C. Assume the iron has a heat loss of 9.2 Kcal, calculate the heater current if the voltage is 110V. (ANS: I = 3.22A)

2. Calculate the value of a bleeder resistor required to complete a voltage divider circuit, designed to supply 210V at 32mA from a 386V source, if the series dropping resistor is 1.3kW. (ANS: RB = 2KW @ 21.7W)

3. Design a voltage divider to supply 110V from a 275V source, if the total drain on the source is to be 0.125A. (ANS: RS = 1.3kW @ 20.6W)

4. Design a bleeder circuit to supply the first load with 10V at 11mA, and the second load with 28V at 0.029A, from a 55V supply. The bleeder current is 92mA. (ANS: RB = 109W @ 0.92W, R1 = 175W @ 1.85W, RS = 205W @ 3.56W)

5. Design a voltage divider circuit to supply 425V at 96mA, from a 525V source. The bleeder current should be 21mA. (ANS: RB = 20kW @ 8.9W, RS = 855W @ 11.7W)

6. With reference to the circuit below, calculate the values and power ratings of RS, R1, RB. The bleeder current is 11mA. (ANS: RB = 2kW @ 0.24W, R1 = 9.1W @ 13.3W, RS = 7.3W @ 66.2W)