Not sure what this symbol is?

[si2030]

Hi all,

I am having trouble identifying this symbol...

View attachment 61837

Its from this schematic...

View attachment 61836

Could someone let me know what it is and what it does?

Kind regards

Simon

 

[PCBWING]

Hi all,

I am having trouble identifying this symbol...
Could someone let me know what it is and what it does?

Kind regards

Simon

View attachment 61841

 

[dr peppers]

Proper name is a tricolour led, tri meaning 3 pins, operation as per schematic above.

There are bi colour too, which is also a dual colour led but with 2 pins, the leds are connected inverse parallel.

From the schematic green is power on, and red is overcurrent.

 

[si2030]

Thanks guys...

 

[PCBWING]

This is the 2 pins'.

Thanks guys...

...There are bi colour too, which is also a dual colour led but with 2 pins, the leds are connected inverse parallel...

View attachment 61906

 

[si2030]

Hi there,

Following on from this I have another related question concerning the use of two diodes in a power supply design I came across from here **broken link removed**..

Here is a schematic of a small power supply which has voltage control and current limit. The system is using the first of four op-amps to display if the circuit is operating in voltage or current mode..

I suspect that when it is in current mode the current sense op-amp is supplying a voltage which then turns on IC1A because the inverting pin goes higher than the non inverting pin.

However, I dont understand how the diode for voltage control is turned on while the diode for current is turned off?

Kind Regards

Simon




Here is the schematic..

View attachment 61908

and here is the detail about this part of the circuit.

IC1A is used as a comparator whose output is used to drive two LEDs that indicate whether the supply is in voltage regulation or current regulation mode. If D2 lights the supply is in constant voltage mode; if D1 lights it is in constant current mode, for example if the output has been short circuited.

 

[unclejed613]

Proper name is a tricolour led, tri meaning 3 pins, operation as per schematic above.

There are bi colour too, which is also a dual colour led but with 2 pins, the leds are connected inverse parallel.

From the schematic green is power on, and red is overcurrent.

actually "tricolor" means 3 colors, red, green, and yellow (with both red and green active at the same time)

the "bicolor" with 2 pins can be made to appear to emit yellow light if AC is applied with a frequency fast enough that the eye blends the red and green together.

 

[DerStrom8]

Proper name is a tricolour led, tri meaning 3 pins

I feel I should mention here that not all tricolor LEDs have 3 pins. Some have 4. "Tri" only means 3, "color" means color. Put it together and you get "3 color"--usually Red, Green, and Blue. "tri" does not necessarily mean 3 pins

 

[ronsimpson]

I think I have a tricolor 2 pin LED.
+ current =red
- current=green
AC current = yellow

 

[MrAl]

Hi,

A two pin LED with two color LEDs in it so that a foward current produces one color and a reverse current produces another color goes by the name of "bicolor" LED, not "tricolor" LED.

One simple rationale for this is that when you only have two LEDs of two different colors you only get two distinct colors and the 'mixed' color would not be a single color really but could be several different colors. So it couldnt really be called tricolor because if we looked at the 'mixed' colors as being additional colors then we'd have to call it an "infinicolor" LED.


The bicolor LEDs do come in at least two different packages however, one with two leads and one with three leads. Obviously the three lead one has a common terminal. I think they also come in four lead packages where they might be driven independently.

The tricolor LEDs have three distinct color LEDs inside, and usually have four leads where one is common to all three. I happen to have picked up a somewhat higher power tricolor a while back and used it as a special indicator. These things work nice for that because you can use the different colors for different meanings that indicate different states of the device you're using it in.
My application was a refrigerator monitor. The operation goes something like this (which illustrates the usefulness of these guys)...
It blinks one somewhat longer WHITE blink to indicate it is about to blink out the temperature, then:
It blinks RED one time for every degree F above 40 degrees F.
It blinks GREEN one time for every degree below 40 degrees F.
It does not blink after the white blink if the temperature is exactly 40 degrees F.
This sequence repeats every 10 minutes.
In between that mode of operation, it blinks one time BLUE every 10 seconds, but it's a very very short blink on the order of 100us. This is just to indicate that the unit is still operating normally and the battery is OK. It's just enough to see the blink without using too much battery power which is two AA size cells.

 

[dr peppers]

To answer your question si,

Your op amp output is either +rail, or -rail (or nearly so if its a bipolar output type op amp) as its configured as a comparator, sounds like you already got that bit.

When the opamp output is + current flows through the anode of the led connected to the op amp output (and ok we'll call it a bi colour because it does 2 colours), which we'll say is red, then through the resistor thats connected down to ground, the other led is reversed biased so its off.

Then when the opamp output changes to low (-rail) current flows from the + rail, through the led current limiting resistor, through the led with its cathode connected to the opamp, into the op amp and down to ground through the op amps transistors, at this point the first led is reversed biased so its off.

If you were to toggle the op amps output high and low very quickly, say 50hz, then the led would flash red/green, and due to your persistance of vision you would see the led as being yellow, the combination of red and green.

Hope this clears things a little.

You could use a tri colour led with a few connection changes.

 

[si2030]

Hi Dr Peppers,

I have done some spice simulation and in the simulation it does switch at high frequency so I guess I would be seeing yellow... what changes would you make to ensure only one or the other activates, or is this not really what you want... do you want it to display yellow to show its entering in a current limiting?

Simon

 

[dr peppers]

If we're talking about the same circuit, the one you posted then this is a linear supply, the current limit will switch on and off depending on the load, C8 looks as though its there to slow down the switching time.

When you turn the current limit down below the load current on the supply the led should change state red/green not go yellow, unless the load is pulling current pulses.