Week 2, 1/18-1/22:

1. What is the role of A/B switch? If you are on A, would B still give you a voltage?

The role of the A/B switch is to show measurements for either the A or B power supply. If you are on A, B will still give you a voltage.

2. In each channel, there is a current specification (either 0.5 A or 4 A). What does that mean?

 The current specification means that the .5A or the 4A is the highest amount of amperage that the power supply will tolerate.

3. Your power supply has two main operation modes for A and B channels; independent and tracking. How do those operation work? (Video)

The two main modes, independent and tracking can be changed by a switch. Independent mode allows A and B to power independently from each other. Tracking can be broken down into two different sub modes. Series tracking puts A and B into series allowing you to have a circuit with 0-48V and .5A. Parallel tracking puts A and B into parallel allowing you to have a circuit with 0-24V and 1A. A video is shown below how to change the output mode. Below is a video showing you how to switch the modes.

This video discusses the independent and tracking modes.

4. Can you generate +30 V using a combination of the power supply outputs? How? (Photo)

 Yes, You put the power supply into series tracking and can set A/B into any combination of voltages that add up to +30V. Pictures of our set up are below. The different voltage between two probes is 30V. However, you can also connect negative B to ground to set negative B into 0 V and positive A into +30V.

This is our circuit board.

This is our power supply.

This is our DMM reading 30V.

5.  Can you generate -30 V using a combination of the power supply outputs? How? (Photo)

Yes, To generate -30V you would switch your terminals around from A and B. Taking the positive red cord and putting it into B's negative and the negative black cord and plugging it into A's positive. Pictures of our set up is below. We used the same circuit as we did for part 4.

This is our power supply.

This is our DMM reading -30V.

6. Can you generate +10 V and -10 V at the same time using a combination of the power supply outputs? How? (Photo)

 Yes, you have to set the negative side of A and positive side of B both to ground. When the wires are set in the correct terminals you should be able to read both +10V and -10V on the same circuit in respect to the same ground. Pictures of our set up is below.

This is our power supply set up.

This is one side of the circuit we measured.

Our DMM read at roughly 10V.

This is the other side of the circuit we measured.

Now our DMM reads at roughly -10V.

7. Apply 5V to a 100 Ω resistor and measure the current by using the DMM (remember the setup in DC 3). Compare the reading with the current meter reading on the power supply. At what angle of the current knob makes the LED light on? If you keep on decreasing the current limit, what happens to the voltage and current? (Video)

 When setting a 100 Ohm resistor with 5V we read that the current was roughly 50mA. At the lowest possible angles the current light came on. When you continue to reduce the current the voltage will also reduce and drop to zero. A video of our work is below.

This video discusses how we were able to reduce the voltage by changing the current.

8. Where is the fuse for the power supply? What is it for?

 The fuse is at the back of the power supply unit. It protects the power supply cord.

9. Where is the fuse for the DMM? What is it for?

The fuse in the DMM is at the front of the unit next to the input terminals. It protects the multi meter's circuity from receiving too much current.

10. What is the difference between 2W and 4W resistor measurements?

When we want to measure low resistance, the 4W resistor will be more accurate than the 2W resistor. 4W means four wires are connected in the circuit to measure the resistor, 2W means two wires are connected in the circuit to measure the resistor.

11. How would you measure current that is around 10 A using DMM?

 To measure current that is around 10A you would break the circuit at nodes you would like to measure and put the probes from the DMM on each end of the broken nodes. The DMM has a max of 12A and should be able to measure any circuit with around 10A current.