CircuitMaker v6.2c oscillator simulation

[flat5]

I have a working crystal checker and have entered the circuit in to CM.
The DC analysis is working.
The AC analysis asks for a source.
I can't find a way to tell the program that the crystal is the source.
I just started with the program today.

I'm unhappy with some of the values of the components and also
want to add a buffer circuit at the emitter so as to have an AC out & DC out.

At 'DC Out' I have an LED with no series resistor. None seems to be required.

The switch is only for the simulation circuit.



View attachment crystalchecker NET.txt

 

[crutschow]

What do you want to examine with the AC analysis? AC analysis is for determining the AC transfer characteristics of a circuit. If that's what you want, you can add an AC voltage source in series with the crystal.

If you want to see the circuit oscillate, then you need to use the Transient Analysis, not AC analysis. But note that it can be difficult to see oscillation in a simulation due to the high Q of a crystal and lack of normal circuit noise to start the oscillation. Sometimes placing an AC source in series with the crystal and having it generate a single short pulse at the start of the simulation can help start the oscillations.

An LED with no series resistor is a very low impedance and will tend to short the output.

 

[flat5]

Thank you, crutschow. I'll try the options you suggest.

I don't really see the need for a voltmeter. An LED tells me if the crystal is functioning.
The output current is too low to bother with a resistor.

As I said, I want to play with component values to improve the circuit. I already changed the emitter resistor from 1k to 500 ohms and that seems to have made a big improvement. The circuit as I found it did not have any capacitor across the battery. Adding that also helped raise the output.
I basically want to play with the cap values now.

For frequency checking I plan to add a buffer perhaps just acting as a digital switch for interfacing to a scope/counter.

At present I'm sending the emitter directly to the BNC connector. Bad form, I know.



Edit: Finale circuit drawn using LTspice. Is there a way to change how components are drawn? Transistors are so BIG. Resistors are ugly too.

 

[flat5]

Added an AC source of .25vac in series with the xtal.
The label says .25vac but the icon of the part shows + & - which confuses me.

Still get a 'no source specified' error.

Spics data says: %D %1 %2 %V

 

[flat5]

I'm deleting the software.
Will find another program.

 

[crutschow]

I'm deleting the software.
Will find another program.

Many on these forums use LTspice which is a free download from Linear Technology. It's learning curve is a little steep but there are tutorials and help files along with many sample circuits to get you started.

 

[flat5]

Thanks again, crutschow.

 

[audioguru]

I'm deleting the software.
Will find another program.

Good. The schematic looked silly with those big black dots on the wires.

 

[flat5]

The blobs are optional
I posted with them so we could see that the nodes were ok.
LTSpice capture does not look nice either. Why the big transistors & resistors?
Orcad looks the best.

 

[audioguru]

Finale circuit drawn using LTspice. Is there a way to change how components are drawn? Transistors are so BIG. Resistors are ugly too.

In LTspice a right click on the schematic allows you to zoom up or down and to fit a little schematic on the page to be huge.

 

[flat5]

Thank you, ag. I'll investigate what you are saying.