Week 1Experiment 1

Breadboard Basics

The goal of Experiment 1 is for you to identify on the breadboard of the ANDY board: which of the rows of pins are connected (shorted)

together and which of the set of pins in columns are connected

together so that you will be able to construct the circuits

properly in the experiments that follow.

Breadboard Basics

ANDY board The breadboard on the ANDY board is the white section with the

rows of pins. It is used to hold components and to allow easily wiring between the

power supplies on the ANDY board to the components and from the component to component to form a circuit.

The squarish holes are where wires or the legs of your components are inserted. Inside each hole is a set of leaf springs that clamp on to the wire or end of the component inserted into the hole.

This is the back surface of the breadboard, which one of the ECE lab staff removed from the board similar to the ANDY board.◦ Some metal strips run horizontally and some run

vertically. These strips create a low resistance connection

between the sets of square holes along the metal strip to allow you to easily connect ends of components together without running wires between them. Wires are used to make jumpers between metal strips.

Maximum frequency of operation is 4 MHz, due to parasitic capacitance

Typical Pattern of Connections

. Your job in Experiment 1 is to determine which set of holes in specific columns and rows are connected by these metal strips on the ANDY board.

An instrument that is used to measure:◦ DC voltage and DC current◦ AC voltage and AC current (RMS values)◦ Resistance up to 200 MW◦ Continuity

Commonly used to determine polarity of diodes◦ Capacitance at 20 kHz◦ Frequency of a sinusoidal voltage◦ Low frequency hfe (or b) of a transistor◦ Temperature

Measured with thermocouple probe.

MY-64 Digital Multimeter

Change the battery in the multimeter.◦ The current 9V battery was inserted when the

multimeter was manufactured. ◦ The battery has about a 1 year shelf life.◦ Errors in measurements can be greater than 10%

when the battery voltage is low. This is greater than the measurement error allowed in

the grading program. Failure to replace the battery with a new one may

cause you to lose points on your post-validation report. There should be a new battery in your parts kit.

Directions are available online at http://filebox.ece.vt.edu/~LiaB/Equipment/DMM/Changing_Battery.pdf

Before you use the DMM

Resistance measurements can be made directly using a digital multimeter (DMM).◦ The probes are inserted into the V/W/T plug or jack (red probe) and

the COM jack (black). Note that the dial on the meter is positioned at the 20k mark within the W measurement region.

Digital Multimeter

The probes that come with the DMM have tips that are too large to fit into the holes on the ANDY board breadboard.◦ Do not force them into the holes as this will

damage the leaf springs within the holes. There are a set of banana jack probes in the probe

kit that is offered by Electronix Express that have smaller tips, which you can use instead.

Or you can use a small length of wire wrapped around each of the original probe tips that you then insert into the holes.

Probes

Banana jacks

Set the dial to the maximum resistance value.◦ When there is only air between the tips of the red and black

probes, the reading on the DMM is in the ‘overflow’ condition as air is an insulator and the resistance of air is greater than 200 MW. A “1” off to the left with no other digits displayed.

◦ When there is a very conducting material placed between the two tips, the measurement should be 0.00, indicating that the resistance of the material is much less than 200 MW. You should rotate the dial to a lower resistance range until you

either reach the lowest range or an ‘overflow’ condition is indicated. In the first case, you should record the measurement. In the latter case, you should set the range to the next highest setting

and then record a measurement.

Resistance Measurements

Follow the pattern described in the laboratory manual to map the position of the metal strips that connect sets of holes (pins) on the ANDY board breadboard.◦ Should you find that the minimum resistance that you

measure between pins that are connected by a metal strip is greater than 5 W, you may have a bad breadboard. Very rarely, the metal strips shift in position during

shipment. Contact one of the the OpEL GTA immediately and show

the GTA the measurement. If the GTA determines that you have a bad board, he will trade your old ANDY board for a new.

Potential Issue