In this common-emitter schematic, what's the symbol that looks like a battery with only 2 plates, marked Vbe?

from http://www.academia.edu/16562038/Bi...eld_Effect_Transistor_by_Amit_Kumar_Kesarwani

 

A single cell battery.

The other Vce has three cells.

 

So, is that an asymmetrical bipolar power supply?

 

I have to disagree; in this context, I suspect the single-cell battery symbol labeled "Vbe" represents a generalized base-bias supply, while the multi-cell symbol represents the supply for the collector and its load resistor.

In other contexts, that single-cell battery symbol might indeed represent an actual single-cell battery; but not here.

So, is that an asymmetrical bipolar power supply?

Uhhh... does it look bipolar to you? It doesn't to me, as both "batteries" establish voltages that are positive with respect to circuit common. "Bipolar" would mean one positive, one negative. Right?

 

Generally speaking, either symbol can be used to represent a single cell or multi-cell battery.
If you want to be pedantic, a cell is not a battery. A battery is more than one cell.
If you wish, you can show a single cell to indicate a small voltage while multiple cells would suggest a higher voltage.

In this particular example of a BJT common emitter circuit, the base-emitter bias voltage is shown as VBE and only has to exceed 0.7V to forward bias the base-emitter junction.

 

Vce should refer to the actual voltage between the collector and the emitter. Vbe should refer to the actual voltage between the base and the emitter. The power supplies used for these would be VCC and VBB (CC and BB should be subscript, rather than just smaller font - I know it is possible to set a subscript at AAC because I've done it unintentionally, but don't know how). If just a single character is used (e.g. Vb) it normally denotes the voltage referred to the circuit common rather than a specific terminal.

HELP! - can anyone tell me how to get into and out of subscript? It would be nice if it were on the tool bar, since it is a very common thing in electronics.

 

on original question - looks to me like nothing more than a crude means of implying difference in magnitude

 

I agree. VBE supply should have been labeled VBB. VCE supply should have been labeled VCC.

(I don't see a subscript option. I use text size 3 to make it look like subscript.)

 

Wow, like 3 different camps! Some say it just means "more voltage" . But are any other electronic symbols vague like that?

Some say it means exactly 3 to 1 cells. Sounds logical, but how do I know how many volts? I think ratio is more likely. But might get unwieldy at 20 mV to 20V

One man stands alone, concluding the single-cell symbol "Vbe" represents a generalized base-bias supply, while the multi-cell symbol represents the supply for the collector and its load resistor.

I need to understand that, and I don't.

VBE supply should have been labeled VBB. VCE supply should have been labeled VCC.

Doesn't Vbe mean 'voltage differential between base and emitter'. I don't understand your labels.

."Bipolar" would mean one positive, one negative. Right?

Without a ground in the middle, unipolar. You didn't mention a ground.

 

You are overthinking this.

Use either symbol to represent a power source. It has nothing to do with the number of cells or the voltage.

VBE is used to represent the voltage between the base and emitter.

VBB has been adopted to mean the supply voltage to the base, since the voltage between the base and the base is zero.

Forget about unipolar or bipolar. What you see in the circuit are two separate and independent power sources. This is simply a theoretical circuit to demonstrate the behaviour of a BJT.

 

Use either symbol to represent a power source..

You're saying the 2 symbols are equivalent and their use in this schematic is interchangeable, correct? That doesn't seem logical.

has nothing to do with the number of cells or the voltage.

Seems some people disagree with you, above.

VBE supply should have been labeled VBB. VCE supply should have been labeled VCC.

If these articles are correct, Vbe, Vbb, Vce, and Vcc are different things.

http://www.learningaboutelectronics.com/Articles/What-is-vbb-of-a-transistor

http://www.learningaboutelectronics.com/Articles/What-is-vbe-of-a-transistor

http://www.learningaboutelectronics.com/Articles/What-is-vcc-of-a-transistor

http://www.learningaboutelectronics.com/Articles/What-is-vce-of-a-transistor

Forget about unipolar or bipolar.

So, forget about what you said about unipolar and bipolar, above?

.

What you see in the circuit are two separate and independent power sources. .

They share a ground.

.

This is simply a theoretical circuit to demonstrate the behaviour of a BJT.

Yes. Is that not what we're talking about?

 

You can stop trying to be too logical

or

go ahead and believe what ever you want to believe.

 

VB is the voltage at base/battery/bathtub, whatever.

I can define VB to be whatever I want it to be, so long as I define it.

I will define VB as the voltage at the base with respect to GND in my circuit diagram.
I will define VC as the voltage at the collector with respect to GND in my circuit diagram.
I will define VE as the voltage at the emitter with respect to GND in my circuit diagram.
I will define GND as the node shown in my circuit diagram.

I will define VBE as the voltage at the base with respect to the emitter.
I will define VCE as the voltage at the collector with respect to the emitter.
I will define VCC as the voltage of my power source supplying my circuit.

If someone else wants to use definitions that are different from mine that is ok with me.

 

It's just a graphic symbol.

The two plates represent a single unit of an electro-chemical cell.
Typically, you might see more "plates" drawn to represent more voltage.

Simple two-plate symbols are used to represent (a) 1.5 v single cells (b) symbolic voltage sources- as in the case of your schematic, Vbe is not a battery or voltage source.

 

The two plates represent a single unit of an electro-chemical cell.

Seems logical.

Typically, you might see more "plates" drawn to represent more voltage.

I'm hearing more support for this view, tho' I think "more than 1 cell" would be more logical.

Simple two-plate symbols are used to represent (a) 1.5 v single cells

Seems less logical to be tied to a specific voltage, what's so special about 1.5v?

(b) symbolic voltage sources- as in the case of your schematic, Vbe is not a battery or voltage source.

In a real world circuit, what is Vbe? A test point?

Thx

 

In the referenced links above, we understand the meaning that the writer is trying to convey though not without faults.
You be your own judge if what he writes makes any sense.

http://www.learningaboutelectronics.com/Articles/What-is-vbb-of-a-transistor

VBB is the base voltage of a bipolar junction transistor, in other words, the voltage that falls across the base of the transistor.

http://www.learningaboutelectronics.com/Articles/What-is-vcc-of-a-transistor

VCC of a bipolar junction transistor is the DC voltage that is supplied to the collector of the transistor.

 

In the referenced links above, we understand the meaning that the writer is trying to convey though not without faults.
You be your own judge if what he writes makes any sense.

http://www.learningaboutelectronics.com/Articles/What-is-vbb-of-a-transistor


http://www.learningaboutelectronics.com/Articles/What-is-vcc-of-a-transistor

I give up. Are you going to tell us?

 

I give up. Are you going to tell us?

Nope. You have to figure it out on your own.

Or you can read this thread.

 

Seems less logical to be tied to a specific voltage, what's so special about 1.5v?

Ever notice that common voltages used in circuits are often a multiple of 1.5V?

1.5 V - 6 V - 9 V - 12 V - 24 V 48 V etc.

This is due to the EMF (Voltage) created by the Carbon Zinc primary cell.
This is what they had to work with back in the day, (1900's) people used multiple cells connected in series,
always producing a multiple of 1.5V.

 

Personally , I don't care how one represents a dc supply be it battery or generator. Its a symbol!!. The actual voltage required to do what it needs to do is governed by the requirements of the design. What would you expect to see if it were a AC signal. One alternator in the base circuit and two (or more) in the collector circuit? I don't think so!