IME 156 Lab Final

Once finished soldering, don't forget to ________ the lead.

"Cut off the excess" of the leads

A crimp connection may look okay after crimping, but should be tested for continuity because:

- Crimps may look correct, but be intermittently failing. - power may not be getting to your system if either of your crimps in Slot 1 or Slot 2 are faulty. - crimping process takes a few tries to become proficient.

Polarized capacitors usually have what two features that indicate polarity?

-A negative stripe along the body near the cathode lead. - A longer lead which indicates the positive (anode).

What tool can be used to remove flux residue "glassy puddles"?

-scratch awl -exacto-knife - isopropyl alcohol w/ acid brush & cotton or paper towels

All component bodies should be reasonably close, but resistors should be within _______ of the PCB surface for maximum points.

1 millimeter

. What are the four basic steps to soldering?

1. Wipe the tip clean 2. Heat the connection 3. Apply the solder to the opposite side of the connection 4. Leave the tip on to melt the solder and create the connection

What length of wire insulation is stripped off to prepare for crimping?

1/8 inch

Each RGB LED has three independent LEDs: a red one, a green one, and a blue one. Including the LED soldered in Region 1, how many independent LEDs would you expect to function in your project?

10

Your RGB LEDs each require three positive and three negative wires. You have three RBG LEDs in your project. Each wire requires soldering at one end and crimping to the other. How many total crimps are required for your project's LEDs?

18

Your RGB LEDs each require three positive and three negative wires. You have three RBG LEDs in your project. Each wire requires soldering at one end and crimping to the other. How many total wire interconnects (solder joints plus crimps) are there for your project's LEDs?

36

Which traditional solder alloy does NOT have a soft (liquid + Solid) state?

63/37 does not have a soft state.

Clean your soldering iron tip with:

A damp sponge

What is solder wick?

A solder wick is a mesh of rosin coated wire that absorbs solder

What are the straight yellow lines connecting devices on your board layout?

Air wires

In the event of a serious injury or person in need of immediate medical assistance, what should you do?

Call 911 from one of the emergency phones located on the wall of the main lab or computer lab. Tell the 911 operator the location: Bldg 192 - Room 105 and the nature of the emergency. Tell your instructor and/or nearest Teaching Assistant about the emergency.

What is the process of creating a circuit diagram?

Create a new project, then create a new schematic.

The tool used to crimp wires.

Crimper

How do you synchronize the footprint to the standard symbol?

Device editor

Which of the following is a Layout verification check?

ERC & Compare to Schematic

. How often should you clean your soldering iron tip while soldering?

Every time you pick it up, wipe it with a sponge

What must you do before sending the board to a manufacturer?

Export with the CAM processor

Attach heat-sink to regulator IC after soldering regulator IC to PCB. T or F?

False

TRUE OR FALSE: A wire with burnt insulation in electronics manufacturing is acceptable.

False

When assembling header pins to a PCB, the long header pins are inserted into the PCB and the short header pins stick out above PCB. T or F?

False

When removing flux residue with acid brush, isopropyl alcohol and paper towel, apply alcohol to entire board all at once. Tor F?

False

TRUE OR FALSE: 40/60 solder has a lower melting temperature than 60/40 solder does.

False, 60/40 has a lower melting temperature

Silkscreen is a necessary layer for the electrical operation of your board. T or F?

False; Silkscreen is only needed to help clarify the values for components, correct placement of components, or identification

A pattern is the physical dimensions of a PCB component. T or F?

False; This is called the FOOTPRINT in Eagle

To maintain the lab in safe, efficient operating condition, tools must be returned to their proper locations and debris swept up at the conclusion of each lab. What is your responsibility approximately 15 minutes before the end of each lab when clean up is announced

Finish your current operation and collect your belongings, put all of your tools away and sweep up the bench area where you were working. Then, offer to assist others with general clean up tasks.

What is the policy for food and drinks in areas of the lab?

Food and drinks are not allowed in the main lab or computer lab to keep all areas and equipment clean and available for working

What is an advantage of keeping your soldering iron tip tinned?

It helps your solder wire melt and flow better, making soldering easier. The coating creates a heat bridge between the tip and the part you're soldering, which increases the efficiency of the heat transfer.

60/40 solder is the most common, what % is tin and what % is lead?

It is 60% tin and 40% lead

The actual design of PCB traces is done in ____________.

Layout

Which components MUST be inserted and soldered flush to the PCB to work correctly?

Male headers that engage with Arduino

Working in the lab with unrestrained long hair or loose hoodie ties is:

Not a good idea because long hair and clothing can be caught in a rotating drill, circuit board or other items you're working on.

If you cut your finger on a sharp edge of metal, don't feel well, or experience any other type of injury, you should

Notify your instructor immediately. They will advise an appropriate course of action, and also respect your privacy.

Where should personal items such as backpacks, water bottles, umbrellas and jackets be stored?

On the storage shelves provided - located as you enter the lab

To protect our feet from injury from sharp or heavy objects, what type of footwear must be worn at all times in the lab?

Protective, closed-toed shoes must be worn when working in the lab beginning the first day of class.

How do you declutter and simplify the air wires to provide the shortest distance between components?

Ratsnest tool

Things get broken under normal use occasionally and that's okay. If you break or find a non-working tool or something that seems sketchy, what should you do?

Report the broken tool, or non-working soldering iron, etc. to a TA or your instructor promptly so they can repair or replace it.

How do you reposition or rotate the text for a footprint?

Reposition attributes

When hand-soldering electronics (and in the IME156 lab) _______ - core solder is used

Rosin Core solder is used when hand soldering electronics

A good solder joint is _____________ and ________ and feathers out to a thin edge.

Smooth and shiny

What is the purpose of flux?

The purpose of Flux is to remove any oxide from the metal before it is soldered

What is the purpose of soldering?

The purpose of soldering is to make a good electrical connection that is also mechanically strong

What is the recommended power rating of soldering irons used for typical electronics work?

The recommended power rating is 25w to 60w for soldering irons

Wetting is indicated by

The soldering feathering out to a thin edge

What are the two main causes of poor (cold) solder joints?

They are caused by insufficient heat or lead movement while the solder was cooling

What are the two elements of traditional solder?

Tin and Lead

What can cause a copper trace to lift and no longer adhere to the PCB substrate?

Too much heat can cause a copper trace to lift

After assembling all the panel mount component wiring and testing Region 1, the space connectors of the on/off switch will require detachment / re-attachment to install in the chassis. T or F?

True

Capacitors should be reasonably close to the PCB surface, but without excessive strain on the leads. T or F?

True

For correct power jack wiring, outer lug (+) is crimped to slot 1 and inner lug (-) to slot 2. T or F?

True

Heat sinks should be attached to LM350 voltage regulators using #6 screw, #6 hex nut and star lock washers. T or F?

True

Safety glasses must be worn when working in the lab whether you're soldering, cleaning flux residue or inspecting your project masterpiece. T or F?

True

Voltage regulator ICs, like transistors are polarized. T or F?

True

When making a solder joint, never apply solder directly to the soldering iron tip more than momentarily. T or F?

True

What four tools can be used to desolder?

Vacuum Bulb Solder Sucker Desoldering Iron Solder wick

Only use machines and tools you have been trained in the proper use of and that you are confident with, because

We want to learn by doing without risking injury to ourselves or others, or cause damage to the equipment that all students use. We get to learn by doing, but also avoid embarrassment by asking to see a demonstration repeated, which will improve our confidence. If we injure ourself or another student, or break a critical piece of equipment, this jeopardizes our learn by doing approach to lab work at Cal Poly

Wearing eye protection whenever anyone is working in the lab (soldering, drilling, working with sheet metal, wire, or electrical components) is extremely important. Which of the following is the best practice for ensuring you are protecting your eyes in the lab?

Wear safety glasses while you or anyone is working in the lab because many activities in the lab can cause injury or blindness in an instant.

What is meant by wetting?

Wetting is when the solder embeds into the surface of the metal leads

What is meant by tinning?

When you coat the tip of the iron with a fresh layer of solder

How is a solder wick used to remove solder?

You put the wick down above the connection, then press the iron on the wick and the solder will be sucked up. Then cut off the solder part of the wick

How is a wire properly attached to a terminal before soldering the wire to the terminal?

You should wrap the wire around the terminal to get a good mechanical connections

Assembling Region 1 only, then testing to verify functionality before proceeding is important because:

a. Provides feedback on the integrity of the assembly so far. b. Simplifies troubleshooting if something's awry. c. It's worth points.

When is it recommended to remove flux residue from the PCB?

after all solder joints are made, but before turning in for inspection

Only ____________ should be within the inner crimp tab in order to make a secure electrical connection.

bare wire strands

A solder joint contour should have a _________ shape.

concave

The power jack and on/off switch chassis-mount components are _________ to the component end of the wire.

crimped

After crimping a wire, check for:

electrical continuity

Crimping is often used to:

electrically connect chassis components to circuitry on a PCB.

The soldering iron tip should contact which of the following during soldering?

lead & solder pad

What is wired to the third, side lug of the power jack (if you have one) in the Prism LED project?

nothing, do not use, it's unnecessary.

The soldering iron tip should be in contact with surfaces to be soldered for how long?

only long enough for the solder to melt, then the iron tip should be immediately removed

Which component must be inserted flush (1 mm) to the PCB to receive maximum points?

resistor

The purpose of the crimp's metal locking tab is to:

secure wire into a plastic connector body

The following is likely to happen if you overheat a PCB trace or pad.

the trace will lift off the board substrate

For ease of inspection, place resistors such that their______ bands are oriented on the right.

tolerance

In a well executed crimp, ____________ should be held within the outer crimp tab in order to make a good mechanical connection.

wire insulation jacket