Measurement and Troubleshooting Techniques

How To Troubleshoot Electronic Circuits

• Fault correction, fault isolation and fault detection.

• Think of the sequence. Try again.

• Fault correction, fault detection and fault isolation.

• Fault isolation, fault detection and fault correction.

Two 10 k ohm resistors are soldered in parallel and when measured with a multimeter that set to resistance range, it shows a total resistance value of 10 k ohm. What could be the condition of the fault?

• One of the resistor is open.

• One of the resistor is shorted.

• Both resistors are alright.

• One of the resistor's tolerance has changed.

To check for continuity of a printed circuit board copper track, is it possible to use voltage measurement to ascertain its continuity?

• No.

• Yes.

• Depends on the type of multimeter used.

• Depends on the type of printed circuit board used.

When a digital circuit board is connected to the power supply, the supply voltage drops to zero.
What is the most likely caused? 

• A short circuit on the board between the Vcc and ground.

• Some of the copper tracks on the circuit board are open circuited.

• The power supply was not set to the correct supply voltage value.

• The use of wrong values on some of the capacitors on the circuit board.

When checking the output of a 3-input AND gate, it shows logic 1' instead of a logic 0'. What is the most likely possibility caused? 

• Its output is shorted to ground.

• All its inputs are set to logic `1'.

• One of its input is set to logic `0'.

• Two of its inputs are set to logic `0'.

Signal tracing is a method used in troubleshooting. It involves

• Tracking the signal from the source to its output.

• using an oscilloscope to monitor the signal at the circuit output.

• Checking for the presence of the signal at the midpoint between the input and output.

• Checking the signal randomly at any stage that has the highest probability of a fault existing

To ensure that a digital IC chip in a circuit board is receiving its power supply, the first step is to check the presence of the supply voltage on the

• outlet socket of the 230V AC mains.

• Vcc and ground of the circuit board.

• the output binding posts of the power supply unit.

• the appropriate supply and ground leads of the IC chip itself.

What is the possible faults the the decoder/driver shown below:

• Wrong inputs.

• Decoder/driver faulty.

• 7-segment display unit, one of the segment faulty.

• No fault.

When you use an ohmmeter to identify a short, the ohmmeter reading should indicate

• Zero.

• Infinite.

• 100 k ohms

• 1 Mega ohms

To be a good troubleshooter in electronics circuit, the attributes are able to 

• understand the theory and operation of the circuit devices and Integrated Circuits (IC) that are suspected to be bad.

• know how to change the parts.

• change the whole board.

• visualise the faulty part.