Free CAST Practice Questions

Question 1

During an authorized zone test, opening a normally closed door contact produces an alarm, but shorting the field cable pair leaves the zone secure. The panel recognizes 2.2 kΩ as secure and approximately 0 Ω as a wiring fault. Its 2.2 kΩ resistor is installed in series with the loop inside the panel cabinet. Which wiring correction restores supervision of a shorted field pair?

Accepted Answer

Move the resistor to the protected end, in series with the door contact.

Answer

Keep the resistor at the panel and replace the contact with a normally open model.

Answer

Add another resistor in parallel with the door contact.

Answer

Move the resistor across the normally closed contact at the door.

Question 2

A fixed-position entrance camera gives a sharp, correctly exposed picture, but visitors occupy too little of the image for useful identification. The view includes substantial unused space on both sides of the doorway. With the camera position and image sensor unchanged, which adjustment directly increases the doorway's optical image size?

Accepted Answer

Increase the lens focal length and refocus on the doorway.

Answer

Use a shorter focal-length lens and refocus.

Answer

Open the iris to admit more light.

Answer

Enlarge the recorded image with digital zoom while retaining the existing lens setting.

Question 3

An alarm installation draws 0.25 A in standby and 1.60 A total in alarm. The design requires 24 hours of standby followed by 15 minutes in alarm, with a 1.25 sizing factor applied to the combined ampere-hour demand. All four battery sizes below are approved for the charger and cabinet. What is the smallest battery that meets this requirement?

Accepted Answer

9 Ah

Answer

7 Ah

Answer

12 Ah

Answer

18 Ah

Question 4

A new camera cable passes a simple pin-to-pin continuity test, yet its Ethernet connection is unreliable. Both ends have the same conductor order at pins 1 through 8: white/orange, orange, white/green, green, white/blue, blue, white/brown, brown. Which termination defect is present even though every pin connects to the same numbered pin at the other end?

Accepted Answer

A split pair affecting the 3-6 and 4-5 pin groups

Answer

An orange-to-green pair crossover

Answer

A polarity reversal within the orange pair on pins 1 and 2

Answer

A transposition of the complete blue and brown conductor pairs

Question 5

A loss-of-power test leaves an electric strike locked against entry from outside. The inside lever still retracts the latch mechanically, and the door opens freely for exit. The approved hardware schedule specifies a fail-secure strike with independent mechanical egress. How should the technician document this result?

Accepted Answer

Expected fail-secure operation with mechanical egress preserved

Answer

Unsafe egress requiring a fail-safe strike before return to service

Answer

A keeper-spring failure that prevents release without power

Answer

A misconfigured request-to-exit input

Question 6

A transistor switches the return side of a 12 VDC relay coil. The manufacturer's circuit calls for a suppression diode to carry the coil's current when the transistor switches off. Where should that diode be connected?

Accepted Answer

Across the coil, with its cathode at the positive terminal.

Answer

Across the coil, with its anode connected to the positive terminal.

Answer

In series with the coil, oriented to conduct its normal operating current.

Answer

In parallel with the relay's switched contacts.

Question 7

An event log records this sequence: bell energizes, communicator restarts, network connection drops. Once the bell is running, a DC voltmeter shows the specified supply voltage at the communicator. Which test is most likely to capture the initiating fault?

Accepted Answer

Capture the voltage at the communicator's power terminals with a triggered oscilloscope.

Answer

Measure the communicator's steady operating current after the bell has reached full output.

Answer

Check the disconnected power cable for continuity with the installation de-energized.

Answer

Measure the transmitter's RF output level during a separate scheduled communication test.

Question 8

During testing in an empty showroom, a PIR detector repeatedly alarms when a radiant heater cycles on. The detector looks directly at the heater; its supply and tamper circuit test normally. A replacement detector of the same model behaves identically. What correction addresses this evidence while retaining intrusion coverage?

Accepted Answer

Reposition the detector to exclude the heater and verify the protected area with a walk test.

Answer

Replace the zone cable with shielded cable to prevent the heater's switching noise from reaching the panel.

Answer

Reduce detector sensitivity until heater cycling no longer causes alarms, leaving its position and coverage unchanged.

Answer

Replace the panel's zone-input module to eliminate the repeated alarms.

Question 9

A composite CCTV camera feeds a monitor, whose passive loop-through output continues over coaxial cable to a recorder. After the monitor is added, both images become dim. The camera is intended to drive one 75 Ω termination, but the monitor and recorder are each set to 75 Ω. Which configuration removes the loading error and correctly terminates the end of the line?

Accepted Answer

Set the loop-through monitor to high impedance and leave the final recorder at 75 Ω.

Answer

Retain both terminations and raise the camera's video output level.

Answer

Leave the monitor at 75 Ω and set the recorder to high impedance so the first device terminates the line.

Answer

Set both inputs to high impedance to remove their termination loads.

Question 10

A 12.0 VDC supply powers a remote alarm device over two copper conductors, each 40 m long with a resistance of 0.025 Ω/m. The device draws 0.10 A in standby and 0.90 A in alarm, and requires at least 10.8 V at its terminals. Ignoring connector resistance, which alarm-state voltage and cabling decision are correct?

Accepted Answer

10.2 V; lower-resistance conductors are needed to meet the voltage requirement.

Answer

11.8 V; the existing conductors meet the device's minimum voltage requirement.

Answer

11.1 V; the existing conductors meet the device's minimum voltage requirement.

Answer

8.4 V; lower-resistance conductors are needed to meet the voltage requirement.

Free CAST Practice Questions

Domain 1: Graphic Arithmetic 15% of exam

Question 1

Domain 2: Mathematical Usage 16% of exam

Question 2

Question 3

Domain 3: Mechanical Concepts 40% of exam

Question 4

Domain 4: Reading for Comprehension 29% of exam

Question 5

More CAST practice questions

Question 6

Question 7

Question 8

Question 9

Question 10

That's 10 of 1,030