Power Supplies

This module will teach you how to use both analog and digital power supplies. While there will be different power supplies in the world in which you will interact, this will gain you the basic knowledge of power supplies to be able to handle any power supply you come across.

The analog power supply we will work with is the model HY3003D-3 and information can be found in this data sheet or user manual. It is important to note that many different manufacturers will make the HY3003D-3 model of regulated analog power supply. While the interface might be different, the circuit diagram is the same.

The digital power supply used is the Rigol DP1308A and information can be found here, specifically under the documents tab and looking at either the data sheet or user manual.

Front of a Rigol DP1308A digital power supply

For this module, you will need:

• Rigola DP1308A digital DC Power Supply
• HY3003D-3 analog DC Power Supply
• 2 Fluke 179 True RMS multimeters
• An assortment of short wires
• Resistors: 10ohm and 10kohm
• A breadboard (or protoboard)
• BNC-Banana Plug Adaptor (with male BNC plug)
• BNC Cables

This module assumes some familiarity with the Multimeters and detail will not always be explained when using these devices.

This module is part of the General Lab Equipment Obstacle Course.

Floating and Grounding

It is important to first discuss the difference between a floating power supply and a grounded power supply.

Ground is a physical connection to the earth (ground). For American three pronged outlets, the extra little third prong will attach to ground.

Floating circuits will have a point of lowest potential, but this value could be anything relative to ground. This is what occurs for American two pronged outlets and batteries. Floating can be used to change voltages when there is already a high voltage occurring. For example boosting 1000V to 1020V, where as a grounded supply would attempt to jump 1000V directly to ground.

Analog Power Supply

This section will cover use of the HY3003D-3 analog DC Power Supply. First discuss the basic nature of the power supply and then discuss the three operating modes.

General Analog Power Supply Information

Front of a HY3003D-3 analog power supply, noting that this particular model does not state it on the front

The HY3003D-3 analog power supply has meaning to its name, breaking into parts HY-30-03-D-3

1. HY- Brand/manufacturer
2. 30- Maximum output voltage (30 volts)
3. 03- Maximum output current (3 Amps)
4. D- Display type (LCD)
5. 3- Number of outputs (3)

There are three outputs on the analog power supply-

1. Floating Constant 5V Output
2. Master Output
3. Slave Output

Constant 5V Output

We will first discuss the constant 5 volt output. First to explore, we use the multimeter in resistance mode to find the internal resistance of the constant power 5V power supply. With the power off, measure the resistance from the positive terminal (red) and the negative terminal (black) of the .

1. What resistance do you read across the constant voltage supply? Does this seem reasonable?

This value is important to know, as the internal resistance of the power supply can affect the desired output of the power supply depending on your load circuit. Now measure the resistance between the positive terminal of the constant power supply and the

2. What resistance do you read? Does this make sense?

The 5V supply by default is a floating supply, so there should be no connection to ground.