Transcript Document

Creating an Astable Circuit
This will guide you
through constructing an
astable circuit.
STARTING OFF: Adding Resistors
When you open Livewire
you should have a a
screen as shown left.
Zoom in to 125% to
make it easier to see.
Select Passive
Components from the
Gallery. Click on the
resistor, drag and drop
the resistor as shown.
Add 3 more and place
them as shown.
STEP 2: Adding Capacitors
Next stage is to add
the capacitors.
Scroll down in the
Gallery window to
Capacitors.
Add an Electrolytic
Capacitor, making sure
it’s the one with the “+”
sign.
While the component is
still selected, rotate it
left by clicking on the
Rotate Left icon.
Add one more as shown
And rotate it right by
clicking the Rotate
Right icon
STEP 3: Adding LED’s
To find LED’s select
Output Components and
scroll down to LED
Add an LED above the
first resistor,
and another above R2
STEP 4: Connections
Now we need to connect
these components
together.
Hold the mouse over
the top of D1 and leftclick to start the
connection.
Drag a line up a short
way and release, then
click again to set a
corner in the connection
Move the mouse right,
so it lines up with the
top of R2, and left-click
again.
Finally click on the top
of R2 to finish the
connection.
STEP 4: Connections
Next connect the top of
R3 to the corner of the
last connection.
Connect the rest of the
components as shown.
STEP 5: Adding Transistors
Select Discrete
Semiconductors from
the Gallery and place an
NPN Transistor below
R1.
The transistor needs to
be mirrored.
With the transistor still
selected, select from
the Menu bar:
Edit
> Arrange
> Mirror
The transistor has now
been mirrored and
should line up below R1.
If not move it so it
does.
Add another transistor
below R4. There is no
need to mirror this one.
STEP 6: Connecting the Transistors
Connecting the
transistors needs
diagonal lines. Follow
the following steps
carefully.
Connect a wire from the
left of C2 to the base
of Q1
Select the wire by
clicking on it.
Now click on the corner
handle and move it left
until the upper part of
the line is at 45
degrees.
Click anywhere on the
screen to deselect the
wire.
STEP 6: Connecting the Transistors
Now for the second
transistor.
Connect a wire from the
right of C1 to the base
of Q2 as shown. Try to
follow it exactly.
Click on it to select it.
Move the top corner
left as shown.
Deselect the line.
Connect up the
remaining terminals as
shown.
STEP 7: Adding a Power Supply
Select Power Supplies
from the Gallery.
Add a 9v Battery to
the circuit placing it on
the left.
Connect the positive to
the top by D1 and the
negative to the bottom
by Q1.
STEP 8: Changing the Values
The values of the
components need
changing.
Double click on R1, an
edit box will appear.
Click on the down arrow
next to the “K” and it
should disappear.
Also change the value to
220
and click on OK
Do the same with the
rest of the resistors
changing them to the
values shown.
Change the values of
both capacitors to 10uF
STEP 8: Changing the Values
Now the transistor
values need to be set.
Right click on Q1
transistor and select
Models
Then select BC337. If
you have a later version
you will see a list box
instead.
Do the same with Q2.
STEP 9: Setting up the Simulation
The timing control
needs to be adjusted so
the circuit can be
simulated accurately.
Select from the Menu
bar:
Tools
> Simulation
> Timing Control…
A box will appear with
timing options.
Next to Mode select
the Accuracy option
and press OK
You can remove the grid
dots by pressing Ctrl+D
or selecting the option
in the
View > Grid Menu
Running the Simulation
Press Play to activate
the circuit simulation.