Circuits

# CEDAR Logic Simulator

We used this program to create circuits with basic inputs and outputs like a switch and an LED. With the basic gates provided, we made an "and," "or," "nor," and a "nand" circuit. We also experimented with inverters.

The picture above depicts the four gates and the inverter we learned about.

## AND Gate

For this "and" gate, the LED will only light up if the first and the second switches are on.

## OR Gate

The "or" gate will make the LED light up when the first or the second switch is on. When both of them are on, the LED will still light up.

## NAND Gate

This "nand" gate will trigger the LED for all times except when both switches are on.

## NOR Gate

The LED for the "nor" gate will only light up when both switches are off. Even When both of them are on, the LED remains off.

## Inverter

Like its name, the inverter will invert whatever the switch inputs. When the switch is off, the LED is on. When the switch is on, the LED is off.

This circuit shows a "flip-flop" circuit. When the middle switch is on, the outer two switches trigger the opposite LED.

If you turn on the outer two switches, then the middle one, and then turn the middle one off again, you can get the two LEDs to blink.

# Binary Numbers

We learned how to count using binary numbers and programmed turtles in NetLogo to count them for us.

The turtles above shows the number five in binary numbers. When the turtle is red, it equals to one; when it's black, it's zero. Since it is "1" in the four and the one column, you can add them to get five.

## Binary Numbers and CEDAR Logic

We used CEDAR Logic and our new knowledge on binary numbers to create a binary adder.

The more complicated looking circuit is the same as the "xor" circuit at the bottom of the image; it just uses "and," "or," and an inverter instead.

# Soldering

We used solder to create a simple LED light up with a battery. Solder is similar to glue except it's metal and permanently connects two metal components.

We also watched a video of Kelvin Doe, who invents circuits with materials he finds in Sierra Leone. He creates inventions that would help his community get through some obstacles such as the lack in electricity.

We connected wires, transistors, resistors, and LEDs onto a breadboard to create an "or" and an "and" gate. We connected the battery onto the breadboard with wires on the corresponding bus.

The first thing we did with the breadboard was creating a simple circuit to power the LED.

This image shows the layout of the components for an "or" gate.

## Transistors

Transistors are made of semi-conductor material that controls the current or voltage. There are three connections called the base, collector, and emitter.

## Moore's Law

In 1965, Gordon Moore observed that the number of transistors per square inch double every year since its invention. This means that the number of transistors will grow exponentially. Experts predict that this law will probably be true for two more decades. Gordon Moore is an American businessman who co founded Intel. The largest number of transistors on a commercially available micro controller is 4.3 billion transistors in Intel's 15-core Xeon IvyBridge-EX.

# Operating Systems

An operating system is a program in a computer than runs basic tasks and manages the hardware and software resources. Android, iOS, Linux, and Microsoft Windows are all examples of operating systems.

## Real-Time Operating System/h2> This type of operating system controls machinery, scientific instruments, and industrial systems. It quickly processes data and serves real-time requests.

This operating system manages a computer to effectively carry out a single task for one user.