A Cold Solder

Overview

For the "A Cold Solder" project, I soldered different electrical components onto a pre-programmed circuit board that lights up LEDs in a pattern when plugged into a power source. Soldering is when you use a tool known as a "soldering iron" to melt a metal so that, when it cools, it joins one or more components.

Preparation

Before starting the project, I practiced soldering on a test circuit board. Below is are two images of my soldering.

Soldering Steps

Step 1: Capacitors, Potentiometer, and DC-ins

First, I soldered the two capacitors, potentiometer, and DC-in components to the circuit board. To accomplish this, I used a "helping hand" (a tool that hold the circuit board in place while you solder). Because the capacitors have polarity (meaning that there as a positive leg, known as an anode, and a negative leg, known as a cathode), I had to be careful to solder the anode to the hole shaped like a square, and the cathode to the circle. The manufacturers of the board used these symbols to help engineers distinguish the polarity of the components. Capacitors are used to store energy temporarily, then quickly release it. Then, I soldered the "DC-in" component. This simply is a port for the power source to plug into. Lastly, I soldered the potentiometer. Potentiometers act like resistors (which restrict current), but they are adjustable.

Step 2: Transistors

Next, I soldered several transistors to the circuit board. Transistors are components that help amplify and generate electrical signals. Because they have three legs and polarity, it was very important that I soldered it with the correct orientation.

Step 3: Integrated Circuits

Integrated circuits are sets of smaller circuits that can be attached to larger circuit boards. In this case, the integrated circuits helped to control the pattern of the LEDs.

Step 4: Resistors

Resistors modify voltage and current throughout a circuit to ensure that components are not damaged. In this case, specifically, the resistors help to make sure that the LEDs are not fried.

Step 5: More Resistors

Step 6: LEDs

The next several steps involve soldering many LEDs in a star pattern. These LEDs are very difficult to solder because they are very close to each other, and fixing solder bridges critical.

Final Result

Here are two images of the final result; there is also a video of me turning the potentiometer that causes the lights to change more quickly. The LEDs light up successfully, and there are no solder bridges.

Problems & Solutions

The biggest problem I encountered through this project was preventing and correcting "solder bridges." A "solder bridge" is when solder unwantedly connects two parts of a circuit. This can cause the circuit to malfunction, short circuit, or even break. In several instinces while soldering, I created solder bridges between components (especially LEDs), but I was able to correct them by reheating the solder and using the soldering iron to disconnect the components. If this had not worked, I could have used special tools (such as a "solder wick") that help remove solder from a circuit.