# Logic Probe

Red LED turns on when input is positive (high)
Green turns on when input is negative (low

The logic probe circuit is a tool which can aid in troubleshooting as its purpose is to "check the logic levels" (Red = High - 6V, Green = Low - 0V). When the loose wire (probe) is placed on an input of output, one of the LEDs turn on to show the logic level. The main two lessons which this circuit taught me were to make the circuit compact from the start and the most effective way of building is to not try and copy the schematic onto the breadboard.

# 555 Timer

The 555 timer circuit lab was second circuit we built and it was the first time we had to use IC chips. The final result, when build correctly, was to have the two LEDs flash alternately "like a railroad crossing sign". The purpose of this lab was to understand the effect capacitors and transistors have on the speed that the LEDs were flashing at.

# Transistor Gates Lab

Truth Tables

The transistor gates lab is an introduction to logic gates and their truth tables. The lab consists of 4 small circuits and each demonstrate a different logic gate. The first circuit only has a positive output when both inputs were in positive. The second circuit was similar in the way it was built to the first but the truth tables were complete opposite. Later I discovered that the first is an AND gate and as the second is opposite, it's called an NAND gate. The third circuit was an OR gate because its truth table was 0 1 1 1 meaning the LED turned when at least one input was in negative. The last circuit was again similar to the one before it and it also had an opposite truth table in which only when both inputs were in negative, the LED turned on. Another thing which I discovered from this lab is the formula for the number of possible outputs ; 2 to the power of the the number of inputs.

# What Did I Enjoy?

The thing which made this experience extremely enjoyable is the challenge this task presented. At first, it was very frustrating because I was over thinking everything and making many mistakes. But these mistakes pushed me to keep trying and eventually i was able to figure out the key to properly building a circuit. This assignment wouldn't have been as fun or gratifying if I had been given a procedure to just follow along. The challenge of figuring things out on my own, helped me understand what, going forward, is the best strategy for me when I am building more challenging circuits.

# What Did I Not Enjoy?

Although I understand the importance of having to make the circuit more compact, especially the logic probe, it was quite frustrating. After much troubleshooting, I had been able to get my logic probe to work but it felt like all that work went to waste as I had to start all over again when I tried to make the circuit smaller. However, this taught me some important lessons like, always remembering to make it compact from the beginning by using little wire and connecting to the closest power rails instead of trying to follow the schematic to the T.

# What Would I Change?

For my circuit, I was trying to make it a little more spaced out because in hope of saying space, I squished all my circuits together. Also, I had spent an ample amount of time on troubleshooting my circuits and next time, I would have made more use of my logic probe circuit to help me so that I wouldn't unnecessarily waste so much time and energy.