600 final Questions Graded A+ And Correct Solutions!!!

Refer to figure, If load resistance R2 is reduced by half, what happens to the zener diode? - ANS Zener current will decrease Referring to the figure, the zener diode is designed to break down at 6VDC. What is the voltage drop across resistor 1, with a constant DC supply of 10 VDC? - ANS 4V An elevator motor rotates at 1200 rpm at contract speed and is geared at a ratio of 40:1. If the motor turns 40 rpm the sheave turns 1 rpm. What is the actual speed of the drive sheave in rpms? - ANS 30 rpm Refer to the figure, for the comparator circuit shown, what will happen to the output if the non inverting input goes more positive than the inverting input? - ANS The output will go to zero. Refer to the figure, for the inverting op amp shown, what is the output voltage? - ANS 25 mv Which term defines the limit of magnetic strength around an inductor even though the current through the coil increases? - ANS Saturation Which of the follow describes how an SCR is turned off? - ANS Voltage is removed from anode to cathode On the fourteen pin DIP IC shown in figure 4 what is the location of pin 14? - ANS Top right A brake coil has an inductance off 4 Henries - ANS The photodiode will conduct current when it detects? - ANS Light What does the circuit in figure 5 represent? - ANS A relay timer A string of temporary lighting has fifteen 100 watt light bulbs. A 15 amp breaker is the max size that can be used with the 14 gauge wire used in this 120 volt circuit. What is the current? - ANS 12.5 A If a circuit has three inductors in parallel of 10, 15 and 20 henries, what is the total inductance? - ANS 4.61 Henries What does the symbol in figure 6 represent? - ANS LED Which of the following statements is correct when testing transistors? - ANS A .7 drop from base to emitter is an indication of a good junction What does the symbol shown below represent? - ANS An SCR What is the length of time required to charge? 500 microfarad capacitor in series with a 10k ohm resistor to the max applied voltage of 125 VDC? - ANS 5 Seconds. 500microfaradsX10kohmX5 Which of the following is correct bout collector current of a transistor? - ANS It is nearly equal to the emitter current The entire cab assembly, including the car sling, cab doors, operator, etc., weighs 3400 lbs. The capacity of the elevator is 2500 lbs. The car must be counterweighted at 40% of the capacity plus the weigh of the car assembly. What is the weight of the counterweight assembly? - ANS 4400 lbs What is the most important property an inductor possesses? - ANS The ability to resist changes in current flow Which statement is correct regarding capacitors? - ANS Placing two captors in parallel increases its voltage capacity Which of the following factors determines the voltage rating of a capacitor? - ANS Dielectric What is usually done to protect large capacitors during charging? - ANS A resistors placed in series with the capacitor.