What is the name and utility of this LTspice component?

crutschow

Joined Mar 14, 2008
31,126
It is a voltage source, the same as V1 in you schematic but with a different symbol.
It is shown as a single cell battery symbol, to indicate that it usually represents a DC voltage source, but it can be specified for any type of voltage output, as can V1.
 
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Thread Starter

mike__MecE

Joined Feb 20, 2022
64
hi mike,
It is a Cell, set V to suit the required voltage.
E
View attachment 280505
Thanks, that makes sense. I looked through all of the symbols under sym but neglected to review the nested folders like misc.
So this would be a battery charging circuit. The circuit is actually from the VISHAY Simulation Notes for SPICE Modelling the PTCTL, PTCCL, and PTCEL tangent to the topic you were helping me with previously. I am going to recreate all the circuits in the app notes for practice.
 

Thread Starter

mike__MecE

Joined Feb 20, 2022
64
It is a voltage source, the same as V1 in you schematic but with a different symbol.
It is shown as a single cell battery symbol, to indicate that it usually represents a DC voltage source, but it can be specified for any type of voltage output, as can V1.
Thank you. I believe this would model a battery charging circuit then? I can't imagine any other reason for the second voltage. source.
 

ericgibbs

Joined Jan 29, 2010
16,792
hi mike,
As the basic Cell has no internal resistance and the V=0 it is often used as a convenient way of measuring the current through a circuit without interfering with the circuit's operation.
E
EG57_ 199.png
 

eetech00

Joined Jun 8, 2013
3,418
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Thank you. I believe this would model a battery charging circuit then? I can't imagine any other reason for the second voltage. source.
No. it is not a charging circuit.

It is a circuit that demonstrates the behavior of current vs temperature thu a PTC (Positive Temperature Coefficient - Thermistor) type device.
V3 is a voltage source but can be used as a "Current Meter" if the value is set to 0 (zero). The current can then be displayed in the waveform viewer by mousing over V3 then clicking V3.
 

ericgibbs

Joined Jan 29, 2010
16,792
hi @eetech00
I have checked and cannot find any record showing an Edit or Deletion of the TS threads or posts.
All editing or changes are logged on the site.

I would like to see any evidence of the alleged editing, and will look into it further.

Moderation.
 

eetech00

Joined Jun 8, 2013
3,418
hi @eetech00
I have checked and cannot find any record showing an Edit or Deletion of the TS threads or posts.
All editing or changes are logged on the site.

I would like to see any evidence of the alleged editing, and will look into it further.

Moderation.
Nevertheless, my reply in post #8 is completely relevant (and accurate to the title of the thread) to the response from the TS.
 

ericgibbs

Joined Jan 29, 2010
16,792
hi Mike,
I am unsure why they have done that in this particular circuit.

I only use that method when working with OPA amps, so that the presence of the Vsrc does not affect the measurements I am making between two points in the circuit.

E
 

WBahn

Joined Mar 31, 2012
27,893
Hi Eric, may I ask why that would be necessary/different from simply measuring the current through the thermistor U1?
It's not necessarily necessary, just a common technique that many people use as standard practice. One utility that it has is of decoupling the current-sensing function from the circuit topology, allowing you to make arbitrary changes to the circuit and just move your current-sensing source to the place you want to measure the current and your waveform displays don't need to be changed. You can also capture the data to a file for post processing and because the device name remains the same, you don't have to change anything in whatever tool you are using to do the post processing.
 

Thread Starter

mike__MecE

Joined Feb 20, 2022
64
It's not necessarily necessary, just a common technique that many people use as standard practice. One utility that it has is of decoupling the current-sensing function from the circuit topology, allowing you to make arbitrary changes to the circuit and just move your current-sensing source to the place you want to measure the current and your waveform displays don't need to be changed. You can also capture the data to a file for post processing and because the device name remains the same, you don't have to change anything in whatever tool you are using to do the post processing.
Ok that makes sense. Thanks
 
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