Building Curcuits From Schematics
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Transcript Building Curcuits From Schematics
Electric Curcuits and
Measurements
Basic Electrical
components and their
functions
Measurements of electrical
circuits characteristics
- Multimeter
- Oscilloscope
- Function Generator
Building Curcuits
From Schematics
Basic Electrical components:
- resistors
- capacitors
- Potentiometers
- Capacitors
- Diodes
- LED’s (light emitting diodes)
Electronic Circuit is a collection of
components that electricity is driven
through to accomplish a task
wire has no resistance
Building Curcuits
From Schematics
breadboard is a
plastic matrix with
holes
Power supply and
ground
Leads of el.
components are
inserted into the
holes
Bus strips holes are
electrically
connected in vertical
direction (used for
power distribution)
terminal strips holes
are electrically
connected in
horizontal direction
(5 holes series only)
Resistors
Resistor – dissipative element that converts
electrical energy into heat.
Ohm’s law V=IR
Defined by voltage-current characteristics –
slop of the voltage-current curve:
Wire-lead resistor’s value and precision are
coded with four colored bands
Bands: a – tens digit, b – ones digit, c- power of 10, tol – tolerance of
uncertainty
Resistors
R ab 10c tolerance%
Example:
a = green, b=brown, c= red, and t= tol = gold
Range of possible resistance values:
R 51 102 Ohm 5%
5100 (0.05 5100)Ohm
4800Ohm R 5300Ohm
Resistors in series:
R=R1+R2
Resistors in parallel:
R=R1*R2/(R1+R2)
Resistors
-
Kirhchoff’s Laws:
Sum of voltages around a closed
loop or path is zero:
N
V
i 1
i
0
- Sum of currents flowing into a
surface or node is zero:
N
I
i 1
i
0
Series Resistors
Curcuit
Voltage divider
- voltage Vs divides between each
resistor
- creates different reference voltages in a
circuit (having single output supply)
V R1
RV
R
i
eq
s
Resistors/Potentiom
eter
Potentiometer or pot – variable resistor
Provide range of resistance values
controlled by mechanical screw, knob or
linear slide:
Capacitor
Capacitor is a passive element that stores
energy in the form of an electric field (as a
result of a separation electric charge)
Consists of conducted plates separated by
dielectric material
Capacitance (C) units: farads
Dielectric material is an insulator that
increases the capacitance as a result of
permanent or induced electric dipoles in
the material
Capacitor
Capacitors in parallel
C = C1+C2
Capacitors in series:
C = C1*C2/(C1+C2)
Diodes
Diode is a pn-junction that passes current
in only one direction (or rectifier)
Analog to check valve
Diodes
Optoelectronic Diodes or Light Emitting
Diodes (LEDs) – emit photons
- positive lead (anode) is longer
Measurements
Multimeter (measurements
in DC circuits)
Oscilloscope
(measurements in AC/DC
circuits
Function generator
(power supply for generation of
voltage waveform)
Measurements/Multi
meters
Multimeter
(measurements in DC
circuits)
-Only measure resistance when
power to the circuit is OFF ;
- during resistance or voltage
measurements multimeter probes
are place in parallel to the circuit;
- in current measurement the
probes need to be placed in series
(you need to disconnect the el.
component)
Measurements/
Oscilloscope
Oscilloscope – voltage-measuring
instrument, capable of recording high
frequency signals (chapter 3.5.4, p. 10 of manual)
Measurements/
Oscilloscope
Basic concepts (see course web-page)
Probe
Self-calibration
Triggering
- determines proper acquirement of data
- options (source,
coupling etc.)
Acquiring Data
Scaling and Positioning Waveforms
- vertical, horizontal
- aliasing etc…
Autoset
Math functions
Etc…
Measurements/
Oscilloscope/Triggering
To ensure that a recording of the signal
from the transducer is made at a correct
time (or synchronized) triggering is used
(see details in manual, p.10)
Triggering synchronizes an oscilloscope
with the event (signal capturing)
Sources of trigger signals:
- input channel (commonly used)
- AC Line
- External
Input channel triggering:
- uses input signal, activate internal
sawtooth generator and initiate
synchronization;
- frequency of the generator is adjusted
to the one of the input signal
- signal trace appears stationary on the
screen
Measurements/
Oscilloscope/Triggering
Auto triggering: depends on time-base
(controlled by SEC/DIV knob)
Time base (p.16, manual) – controls how
often the values (of a signal) are digitized
Measurements/
Oscilloscope/Scaling
and positioning waveforms
You can change size, scale and position of the
wave form on the display (vertically and
horizontally, using SEC/DIV knob)
Aliasing – occurs when the oscilloscope does
not sample signal fast enough (check it using
SEC/DIV knob)
Measurements/
Oscilloscope/Menu
Control buttons
SAVE/RECALL – restore factory settings
Measurements/
Oscilloscope
Taking measurements
(p.37-39,
manual)
- using autoset (when signal amplitude or
frequency unknown)
- automatic measurements
- two signals measurements: