clapp oscillator

Hi,

Design requirements:

12 Volts supply
output: 3 V peak to peak
frequency of oscillation: 1590 Hz

We already have a partial design.
It's a common emitter amplifier connected to the clapp oscillator.
We are getting approximately 8 Volts pk to pk on the simulation.
Can you suggest any other ways to accomplish the requirement?

I'll post our partial design later.
Many thanks.

By the way, I am measuring on top of R5.
I just added R5 and made it a very high value so it acts like open.
I wanted to measure below C6 and R5 should not be there
but I could not figure out how to add test points.
One thing more, I also want to see in the simulation
the frequency of oscillation without manually computing it.

here you go:

Net (Node) labels (test points?) are placed using the Label Net tool in the toolbar (looks like a square bubble with an A.)
All nets are collected during simulation, and can be plotted even if you don't put an explict label on them. After a simulation run, put the Red Probe on a labelled or unlabelled node, and it will show you the internal node number, as well as the dc operating point.

To show the frequency of a plot trace, right mouse click on the trace label at the top of the plot pane. In the dialog box, Pull down 1st & 2nd in Attached Cursor. Click OK. That puts two superimposed cursors on the plot. Drag the 1st to the peak of the trace. Drag the second to a peak one cycle later. See my example.

Your frequency is off.

Use a real NPN; the generic one is a whimpy device.

Your circuit has some flaws.

Hi sir,

The frequency should be 1590 kHz.
I'll try to do what you said in your reply.
I'll come back later to show what I have.

Hi,

Groupmates decided that we use a 9013 transistor.
I found this spice model on the yahoo groups.

.model SS9013 npn is=3.40675e-14 bf=166 vaf=67 ikf=1.164 ise=12.37f ne=2 br=15.17 var=40.84 ikr=0.261352 isc=1.905f nc=1.066 rb=63.2 irb=5.62u rbm=22.1 re=0.02 rc=0.7426 cje=3.53e-11 vje=0.808 mje=0.372 cjc=1.74e-11 vjc=0.614 mjc=0.388 xcjc=0.349 xtb=1.4025 eg=1.0999 xti=3 fc=0.5 Vceo=20 ICrating=0.5 mfg=Fairchild


Problem is, I don't know how to use it.

Added later: Ok now. library now updated

Beta we measured on our transistor is 210. However, the model's bf=166. What do I do? Should I change it?

I don't know if the transistor is defective. Datasheet says its hfe min is 64 and max is at 202.

Nah! Now confused with hfe and beta. I thought they are the same.

hFE is DC current gain. hfe is AC current gain. Beta is one or the other.
Each transistor has a different hFE even if they have the same part number so we design a circuit so that EVERY transistor works.