Elen142 Fabrication II Exam Quiz!

Tinning a wire before wrapping it around a turret post is important because it helps to improve the conductivity and durability of the connection. Tinning involves coating the wire with a thin layer of solder, which not only prevents oxidation but also provides a better contact surface. This ensures a more reliable and efficient electrical connection between the wire and the turret post. Additionally, tinning helps to prevent the wire from fraying or unraveling during the wrapping process, making it easier to secure the wire firmly in place.

Reference designators are used in engineering and electronics to identify specific components or parts on a circuit board or schematic diagram. These designators typically consist of a letter followed by a number. It is a standard practice for reference designators to always start with a letter, indicating the type of component or part being identified. Therefore, the statement "Reference designators always start with a letter" is true.

During the soldering process, copper and solder are heated to a melting point, allowing them to combine and form a new alloy. This new alloy is a mixture of copper and solder, which creates a strong bond between the two materials. Therefore, the statement that the copper and solder combine to form a new alloy is true.

Kevin says no. Zander says yes. James says no. Brad says yes. I don't know anymore...

The answer is 60/40, 63/37, 50/50. These are the three most common leaded solder alloys used in various industries. The numbers represent the percentage of tin (Sn) and lead (Pb) in the alloy. The first number indicates the percentage of tin, while the second number indicates the percentage of lead. For example, 60/40 means that the alloy contains 60% tin and 40% lead. These alloys have different melting points and properties, making them suitable for different applications.

The correct answer is 60% Tin, 40% Lead. This is because solder wire labeled as "60/40" typically refers to the ratio of tin to lead in the solder composition. In this case, it means that the solder wire is made up of 60% tin and 40% lead.

Corrosive, acid-paste flux is not suitable for use on printed circuit board assemblies because it can cause damage to the components and the board itself. This type of flux is highly corrosive and can eat away at the metal traces on the board, leading to short circuits and other issues. It is important to use a non-corrosive flux specifically designed for electronics when working with printed circuit board assemblies to ensure their proper functioning and longevity.

Rosin-based fluxes are inactive at room temperature because rosin is a solid substance that needs to be heated in order to become active. At room temperature, rosin remains in a solid state and does not have the ability to effectively remove oxides and contaminants from metal surfaces. Therefore, it is true that rosin-based fluxes are inactive at room temperature.

During the soldering process, the connection is brought to 40°C above the melting point of the solder for 2-5 seconds. This increase in temperature helps to ensure that the solder melts and forms a strong bond between the components being soldered. The short duration of 2-5 seconds is necessary to prevent overheating and potential damage to the components.

In a block diagram, off-board components should be enclosed in a box made out of dotted or dashed lines. This is because dotted or dashed lines are commonly used to represent components that are located outside of the main system or circuit. These components are typically connected to the main system through external interfaces or connections. By using dotted or dashed lines to enclose off-board components, it helps to visually differentiate them from the on-board components and indicates that they are separate entities.

The given answer "63/37" refers to the composition of the eutectic solder alloy. In this case, the alloy is made up of 63% tin (Sn) and 37% lead (Pb). Eutectic alloys have a specific composition that results in the lowest melting point, allowing for easier soldering. The 63/37 eutectic solder alloy is commonly used in electronics and electrical applications due to its desirable properties such as good wetting, low surface tension, and minimal formation of brittle intermetallic compounds.

The core of a soldering iron tip is usually constructed from copper because copper is an excellent conductor of heat. It allows the heat to transfer efficiently from the heating element to the tip, ensuring that the solder melts and flows smoothly. Copper also has good corrosion resistance and high thermal conductivity, making it an ideal material for soldering iron tips. Zinc, iron, and nickel are not commonly used as core materials for soldering iron tips due to their lower thermal conductivity and other properties that make them less suitable for this application.

When a wire is connected to a turret post, it needs to be wrapped around the post to ensure a secure connection. Wrapping the wire around the post for 180 degrees provides a sufficient amount of contact between the wire and the post, ensuring a strong and stable connection. Wrapping the wire for any less than 180 degrees may result in a loose connection, while wrapping it for more than 180 degrees would be unnecessary and may cause the wire to overlap itself, potentially leading to damage or interference.

The wetting action refers to the process in which an intermetallic bond is formed between the metals comprising the component termination and the PCB pad. This bond is essential for ensuring a reliable and stable connection between the component and the PCB. The wetting action involves the solder material spreading and adhering to the surfaces of the metals, creating a strong bond.

The outline of a wire soldered to a turret post should be discernible.

A wire list should include the Net Number, Net Name, and Net Connections. This information is crucial for understanding the connections between different nodes in a circuit. The Net Number helps in identifying and distinguishing between different nets, while the Net Name provides a descriptive label for each net. The Net Connections section lists the specific nodes that are connected to each net, enabling proper circuit analysis and troubleshooting. Including these details in a wire list ensures accurate documentation and facilitates efficient circuit design and maintenance.

The wire connected to a turret post must be wrapped a maximum of 270 degrees around the post. This is because wrapping it more than 270 degrees would cause the wire to overlap itself and potentially cause damage or interference. Wrapping it less than 270 degrees would leave the wire loose and insecure, risking disconnection. Therefore, 270 degrees is the maximum safe and secure amount of wrapping for the wire around the turret post.

The solder composed of 99.3% Tin and 0.6% Copper is commonly known as SN100. The "SN" in SN100 stands for "tin" (from the Latin word "stannum") and the number "100" represents the tin content percentage. This type of solder is widely used in electronics and electrical applications due to its high melting point, good wetting properties, and low risk of tin whisker formation.

SAC305 is the correct answer for the composition of solder that is commonly known as 96.5% Tin, 3% Silver, and 0.5% Copper. The acronym SAC stands for "Silver, Tin, Copper," and the number 305 represents the percentages of each element in the solder composition. This type of solder is widely used in electronics manufacturing due to its excellent thermal and mechanical properties.