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 one more as shownAnd rotate it right by clicking the Rotate Right icon

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.

STEP 3: Adding LED’s

To find LED’s select Output Components and scroll down to LEDAdd 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 left-click 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 220and 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 optionand 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.