Fault Finding Test
What do Fault Finding Tests assess?
Fault Finding Tests, also known as fault diagnosis tests, are designed to measure a candidate’s ability to diagnose faults in electrical and mechanical systems. It demands a high level of concentration because candidates are required to understand how different inputs are changed by 3 separate switches. Fault finding tests are particularly useful in jobs that require precision and a strong technical understanding.Typical roles that would use our Fault Finding test:
- - Technical Roles, e.g. electricians and engineers
- - Operational Roles, e.g. maintenance
- - Armed Forces Roles
Overview of the Fault Finding test
This Fault Finding Test consists of a total of 25 questions that must be completed in 20 minutes. In the test there are always 2 parts to each question:
There are a total of 7 switches that are used throughout the test. Each question is made up of 3 switches and each switch modifies the input before the next switch in the series. This grid shows all the functions that each switch performs:
The first switch (a triangle symbol) inverts inputs 1 and 2. That is, if the input is on, it is turned off and if it is off it is turned on. All other switches act in a similar way as shown in the grid. If a switch has a fault then it has no effect on the input, so it passes through unchanged.
In this example question, all inputs 1-4 are off (black).
Switch A: When these inputs pass through switch A, inputs 1 & 2 are inverted (i.e. switched on). This gives (1=on, 2=on, 3=off, 4=off).
Switch B: When these inputs pass through Switch B, inputs 2 & 3 are inverted. This gives (1=on, 2=off, 3=on, 4=off).
Switch C: When these inputs pass through Switch C, inputs 1 & 4 are inverted. This gives (1=off, 2=off, 3=on, 4=on).
How to do well in your Fault Finding Test
To do well in a fault finding test, it is good to implement the following tips…
1. Familiarise yourself with the switch grid first – The switch grid does not change throughout the test, so it is worth familiarising yourself with this first to save time. Similarly, for each question set, there will be multiple questions about the same switches, so it is best to look at these switches and follow tip 2 at the beginning of each set.
2. Convert the switches into input changes – The key to finding the fault is to mentally convert the information on the switch grid into the expected number of changes in the input. For instance, if there are 0 or 2 switches inverting a certain input, then that input should remain the same, and if not, then there is a fault. Similarly, if 1 or all 3 switches invert an input, then there should be a difference between input and output.
3. Don’t be fooled by a lack of visible change – Remember that to pass through the circuit, there are 3 different switches. As such, no visible change between input and output can just as easily represent a working circuit or a faulty switch. Similarly a visible change could easily mean that a circuit is not working properly. This is no shortcut to getting the right answer.