Elementary Q: Regarding Feedback Cct

[strokebow]

Hi,

In the attached circuit. Is this correctly drawn circuit diagram?
What is general name for this type of circuit?
Also I believe this circuit is working like this: The circuit operates by sensing the Iem current between Fil and source compared to a fixed demand input. The other current (2-5A) in the I filament is then regulated in order to maintain the Iem current.
Is there a better way to explain this? What are the different components and what are they doing? i.e. how does this work and can it be represented in a better way (with proper cct components) and correct terminology?

Thank u for ur help and comments. I am novice.

 

[Audioguru]

The filament gets hotter when its current increases. The part you call "source" can be a temperature sensor that provides negative feedback so that the temperature of the filament does not change.

 

[strokebow]

Thank you for your reply.

Are you saying this is a negative feedback amplifier? Also what is the triangle symbol in the attached. It looks strange?
If you or anyone can provide more details I would be very thankfull

 

[Audioguru]

If you do not have negative feedback then the temperature is not controlled. Instead you could detect over-temperature then have something turn off the power until it cooled to a low temperature then something turns on the power again. But then the temperature jumps up and down.

The triangle is an amplifier with a non-inverting input and an inverting input. Usually it is an opamp. The rectangle is a transistor, darlington transistor or Mosfet to provide the fairly high output current.