Download Week 1

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