Circuit Testing and Troubleshooting

Verify that the power supply is correctly connected to the circuit before turning it ON. Also make sure that the power supply volatge is proper value (5 Volts). Then and only then should you turn ON the power to the circuit.

Breadboard logic circuits can be manually tested using a digital test system such as the logic probe, logic pulser, curent tracer and logic analyzer. Logic probe is the most useful when it is necessary to trigger gates, flip-flops, counters or other types of circuits to check for proper operation. the current tracer is more specialized test probe used in locating shorts in digital circuits. Whenever a short circuit is suspected, the current tracer can asist the troubleshooter in pinpointing the exact location of the short. The logic analyzer is a complex instrument used to compare many different logic signals at one time. However, it is expensive and is used mostly in complex systems to solve the more difficult problems that occur in digital systems.

When implementation circuits on logic experimenter kit, the circuit can be tested by connecting logic switches on the experimenter kit to the circuit's inputs and the LEDs of the experimenter to the circuit's output. Apply various input logic levels with the switches and monitor the output produced by the circuit with the LEDs. List the resultant functional operation of the citcuit in a truth table if necessary. Determine if the circuit is operating properly.

If the circuit does not function accordingly or if an IC gets very hot or starts smoking, turn OFF the power supply and all signals to the circuit IMMEDIATELY.
Use the suggestions given in the Troubleshooting checklist below to troubleshoot the malfunctioning circuit.
 

Troubleshooting Checklist
 
 
* Do the parts used in the circuit match the schematic?  
* Have the pin numbers been identified correctly in the schematic?  
* Are the parts inserted correctly in the breadboard?  
* Is the correct volatge supply being used to power the circuit?  
* Is the power properly connected to each pin?  
* Are there any wires shorted to one another?  
* Is the circuit wired correctly?  
* Has the circuit been anlayzed correctly?  
* Has the circuit been designed correctly?