Siemens Level 1 Electrical #1

A sudden increase in the total current, in a parallel circuit, as shown below, may indicate:

• A short circuit.

• A drop in source voltage.

• A blown fuse.

• An open resistor.

• None of these.

Which of the following output voltages based on the float position of an automotive fuel level sensor, as shown below, is correct?

• Full: 12 V Half Full: 6V Empty: 0V

• Full: 0V Half Full: 6V Empty: 12V

• Full: 10V Half Full: 5V Empty: 0V

• Full: 0V Half Full: 5V Empty: 10V

• Full: 8V Half Full: 4V Empty: 0V

In a voltage divider circuit, as shown below, the individual measured voltage drops across resistors R1, R2, and R3 are greater than the calculated values. What is the possible malfunction?

• R4 is shorted.

• The fourth resistor is open.

• Resistor R1, R2, or R3 is open.

• R1, R2, or R3 is shorted.

• None of these.

The voltage divider circuit board, as shown below, does not provide the specified voltages: 24 V at pin 3 and pin 4, all other pins have 0V. The voltages specified with respect to the negative terminal of the power supply are given:

Pin 1: negative terminal of the 24 V power supply

Pin 2: 5.4 V ± 5 %

Pin 3: positive terminal of the 24 V power supply

Pin 4: 20.8 V ± 5 %

Pin 5: 16.0 V ± 5 %

Pin 6: 14.6 V ± 5 %

Pin 7: 12.0 V ± 5 %

The circuit does not provide the specified voltages. Identify the likely fault for the following case: 24 V at pins 3 and 4. All other pins have 0 V.

• There is an open circuit between pin 4 and pin 5 (R5 open).

• There is a solder splash between pin 4 and pin 5.

• There is a cable break between pin 1 and the negative terminal of the 24 V power supply

• There is a solder splash between pin 6 and pin 7

• There is an open circuit between R5 and R6.

The circuit below shows a basic panel illumination circuit schematic. Which of the following statements about the functionality of the panel illumination circuit, as shown below, are correct? Two Answers are correct.

• The fuse is for circuit protection in case of a short circuit

• The brightness of the lamp is proportional to the amount of current through the lamp

• The brightness of the lamp is proportional to the resistance value of the potentiometer

• If the moving contact (wiper arm) of the potentiometer is disconnected from its resistive element, the amount of light on the instrument is at its maximum.

• In the case of a cable break between switch and potentiometer, the fuse should be blown

In the crankshaft position sensor, as shown below, the induced voltage across the coil is caused by …

• ... a tab passing through the magnetic field.

• ... acceleration of the steel disk’s rotational speed.

• ... rotation of the steel disk

• ... current in the coil.

• ... none of these.

When the needle of an analog ohmmeter indicates infinity, the resistor being measured is:

• Shorted

• Open

• Reversed

• Overheated

• None of these

110 V AC is applied across the primary winding of a transformer. When you check the voltage across the secondary winding, you get 0 V. Further investigation shows no primary or secondary currents. The cause of the malfunction is:

• The primary winding is open.

• The primary winding is completely shorted

• The primary winding is partially shorted

• The secondary winding is open

• The secondary winding is completely shorted.

Based on the control settings, find the peak-to-peak amplitude and the period of the waveform displayed on the scope screen and calculate the frequency.

• Vpp: 0.9 V Time: 0.1ms Frequency: 10Khz

• Vpp: 0.9 V Time: 0.5ms Frequency: 2.0Khz

• Vpp: 1.8 V Time: 1ms Frequency: 1.0Khz

• Vpp: 1.8 V Time: 0.5ms Frequency: 2.0Khz

• Vpp: 2.4 V Time: 1ms Frequency: 1.0Khz

A 3.3 kΩ resistor has burned out in a circuit. You must replace it with another resistor with the same resistance value. If the resistor carries 50 mA, what should be its power rating? Assume that you have available resistors in the following power ratings: ¼ W, ½ W, 1 W, 2 W, 5 W, 10 W, and 20W.

• 10 W

• 1 W

• 5 W

• ½ W

• 2 W