Step-up, Step-down, and Isolation Transformers

Are the transformers connecting power plant generators to high-voltage power lines considered step-up or step-down? Explain your answer.

A soldering gun is a tool used to quickly heat electrical connections for soldering. Too bulky for printed-circuit board (PCB) applications, it is better suited for point-to-point wiring applications where large wires are to be joined to metal lugs and to other wires.

In addition to being a useful soldering tool, this device is also an excellent example of a step-down transformer. Explain how the construction of a soldering gun employs a step-down transformer (with a very large step ratio!) to generate high temperatures at the soldering tip.

The circuit shown here has a problem: the lamp does not light up, even though the AC power source is known to be good. You know that the circuit used to work just fine, so it is designed properly. Something in it has failed:

Identify one component or wire fault that could account for the lamp not lighting, and describe how you would use test equipment to verify that fault.

One failed wire or component in the circuit that could possibly account for the problem, and the type of fault (open or short) you suspect it would be.

Identify the type of test measurement you would take on this circuit, and where you would take it (identify the test points you would measure between) to verify the suspected fault.