Simulation LTspice output

[mathew086]

I would like to know the output of this circuit. I would like to get the output based on various values of C1. The inital value of C1 = 10pF. It changes from 10 pF to 500pF ( with a step of 1pF or evenin 10 or 100 pF)

I am quite new to LTspice and so any help would be great. Please explain how to obtain the graph so that i can try out for other circuits also...

Thanks

 

[BrownOut]

Add a ground and simulate it. Ground symbol should connect to the battery "-" node.

 

[mathew086]

WHat should i do in the simulation command??? There are many options like DC sweep , Transient, etc.. How can i get the output graph wiht varying values of C1?? WHich one should i select?

 

[BrownOut]

Just set the "stop" time to whatever you think is long enough to run a good simulation. You can worry about all the other stuff later. You may run several simulation and change the value of C1 for each, or use the .step param command. Search for this command in the help unility. Click the ".op" on your tool bar and type in your command. Make sure to drag and drop it on your schematic. Then, type in, for the capacitor value "{PARAMATER_NAME}" Use the curly braces, and the PARAMETER_NAME should match the name on your .step param command.

 

[MikeMl]

I fixed it for ya. You can at least read the schematic now. I show you several LTSpice features, including setting initial conditions, using ground symbols, using a parameterized capacitor value, using abreviatations to make the values more readable, etc.

 

[audioguru]

A 555 will not work with resistors and capacitors that have so many zeros.

I didn't count the zeros but it looked like a 10M resistor and a few pF capacitors.

Instead of 1000000 ohms I enter 1000k into Lt Spice. It doesn't accept 1M ohms.
Instead of all the zeros for small capacitors use uF, nF or pF.

 

[BrownOut]

Great point, and that illustrates one of the problems with circuit simulators. You need to have a good understanding of electronics to interpret simulation results. If you don't, then it's good to check with someone before accepting that your circuit will work.

 

[MikeMl]

... It doesn't accept 1M ohms.
....

It does accept 1meg for 1,000,000Ω

 

[audioguru]

I never tried 1meg. I also don't write 3.3thou, instead I write 3.3k.

 

[BrownOut]

1 meg is consistant with conventional metric used in electrical specificaions. Thou would not be consistant, thus kilo is used ( abbrev. as k ). Both meg and k are acceptable in Spice.

 

[MikeMl]

1m is taken as milli; 1meg is taken as 1e6

 

[audioguru]

Maybe her name should be Meg instead of meg.

 

[BrownOut]

It's actually case insensitive.

 

[mathew086]

I tried simlation using an online simulator
Circuit Simulator Applet
It accepted 1M Ohm and 10MOhm. But the ouptput was not so clear and cannoted be investigated in small parts. That is why i opted LTSpice.

Hey mike thanks for the example. Now i understood how to set parameters for changing C.
Now am trying by changing various paramters and checking..

Thank you guys...If any problem comes , i ll come back sooon

 

[mathew086]

Thanks guys...I am now trying to change various parameters and checking. I ll post if any problems come.....

In the beginning i was using an online simulator Circuit Simulator Applet

But we cannot see the output as we need, that is whuy i opted to LTspice.$
thankss$

 

[Sceadwian]

Look in the help file for "General Structure and Conventions". It's all listed there in black and white...

Always read the manual. I haven't read the whole thing but if I had I'd have found the solution to a problem I'd been searching for a solution on the net for quite a while. You'll also learn things that you didn't know about the software it has quiet a few tricks up it's sleeves.

 

[mathew086]

Halloo

Is it possibel to calculate the currennt consumption or charge charge consumotpion in a circuit using LTSPice.

Can anyone help in finding out the total charge consumed by this circuit.
Or just the total current consumed ( CHarger = current *time)

timers 555 have a maximum current consumption of 130uA.and for the amplifier it is 2.5mA.

Any help??

 

[BrownOut]

Look for a PM

 

[audioguru]

timers 555 have a maximum current consumption of 130uA.

No.
you show high current NE555 ICs that have a supply current of typically 6mA each.
The Cmos version is an LMC555, TLC555 or ICM7555 and they have a supply current of only 130uA each.

 

[mathew086]

yes i am using a CMOS LMC55CN. so it have 130uA current consumption. , right? or ìs supply current and current consumption are two different things????