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Circuit Setup, Testing, and Measurements
There are different ways assembling a circuit. These include:
- Using point to point soldering,
- Using a printed circuit board ( PCB)
- Using prototyping breadboards
The second method is a professional method and is used in manufacturing. PCBs may
be made by several methods, including the use of CAD software such as PSpice to
generate the output file needed for aiutomated manufacture of PCBs.
In the third method, you place your components on the board that consists of a
matrix
of holes and make the connections using wires that go into holes. In this case, there is
no need for soldering. This method may be convenient for laboratory experiments or
a demonstration of a project. It is also cost effective since a general-purpose board is
used. There are different sizes for breadboards that can be used for different size
projects.
They allow you assemble circuits that include active (e.g. microchips, transistors, etc.)
and passive (e.g. resistors, capacitors, etc.) components easily with a minimum of wires.
Some of these holes are internally connected together, and there is no need for using
solder.
The figure below shows an example of a breadboard.
The middle part of the board is made for microchips that are placed as shown below:
The following shows the correct and incorrect setup components on breadboards.
NOTES:
 | Rows A and B at the top and bottom of the breadboard are the power and ground bus
connections. All the holes labeled A are connected together, also holes labeled B are
connected together, while, A and B are not connected together. |
| The rest of the breadboard consists of columns labeled 1 through 30. Columns a, b, c,
d, and e are connected together. Similarly, column f, g, h, i, and j are connected
together. |
| A wire, resistor, capacitor, and a microchip (IC) are shown. The IC is placed so that
all pins of the IC are not connected to each other by the internal connections. |
| Remember, when connecting an IC on the board, each column is only one contact point,
so the columns used by the IC are not to be used for other connections of other
components. The figure shows the improper connections. |
Test and Measurements
There are different ways to test a circuit to verify the design.
- Using multimeters
. Digital multimeters are used to measure currents, voltages, or
resistances. If your project requires testing an output analog voltage, this method
may be sufficient. For instance, if you are building an analog amplifier, you may
need to measure the input and output voltages to verify the voltage gain.
- Using Oscilloscope
s. Oscilloscopes display the output on a screen. This method is
very useful for analog and digital applications.
- Using display devices and speakers
. This method is useful if you need to display
data on a screen or seven segment display. A typical project that uses displays
is an Up/Down counter. Speakers are used to verify an audio output such as
music synthesizers, audio amplifiers, etc.
NOTE: The display devices, speakers, and multimeters are available for student use.
Contact the Teaching Assistant of the course for details.
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