The short circuit could generate enough heat to damage your circuit. The problem with simply connecting the input to Vcc occurs when you press the button and create a short circuit between Vcc and GND. You might be tempted to solve the problem with a solution seen in Figure 2. Such sources include thermal noise and electromagnetic interference (EMI) since the leads of the chip act like tiny antennas when they are floating. By not being connect to a source, Vcc, or GND, the I/O pin is susceptible to electrical noise that makes the I/O randomly fluctuate between low and high. The microcontroller may register a low, but it might just as well register a high. But this is not the case because the gate is not connected to ground rather, it is floating. Now, what happens when the button is released? If you were like me you would assume the microcontroller, now that it is no longer connected to Vcc, would register a logic low. When the momentary button is pressed it connects the I/O pin to Vcc and the microcontroller would register the input as a high. To best explain a floating input and how it can negatively affect your project consider the circuit in Figure 1: One of the most basic of the faults is the infamous вЂњfloating pinвЂќ or вЂњfloating inputвЂќ that can affect the I/O pins of digital integrated circuits. Many times these faults are fixed with a very simple tweak to the circuit design or component selection. I highlighted the importance of troubleshooting in this earlier blog post regarding my work on the automated energy harvester. When you are just starting off in electronics, there are many design pitfalls that can lead to hours of frustrating troubleshooting.

Multisim 10 pin transformer