You state the you want to run 96 LEDs is that a string of LEDs in series? If it is then you have other problems with a 20 mA constant current. PubChem CID: Chemical Names: ; N,N-Bis(2-chloroethyl) allylamine; ALLYLAMINE, N,N-BIS(2-CHLOROETHYL)-; TL ; BRN ; . tl has been an eBay member since Jun and has % positive feedback. Check out tl’s full profile.
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This does increase the power dissipation in the transistor, but it’s well within it’s ratings. I will try when I’ll have time and probably come back here. Papou I get it that you don’t have a fixed Rl341 reference. The circuit of Figure 38 seems non-ideal for your application if it’s a string of LEDs you want to driveand Figure 39 modified slightly may be better: I typically tl3441 2 – 3ma and no more than 15ma into a tl So, I want a low Ik at 1 mA.
Are you serious about 69 LEDs in series? I suspected over-voltage peaks and that current limiting is something to try. Another concern is that rather much less that 19mA flows in RCL.
N,N-Bis(2-chloroethyl)propenamine | C7H13Cl2N – PubChem
So you’d need to have capacitance to reduce the ripple. So your circuit looks like the middle one, shown above.
Post as a guest Name. The 2N is only 40 V Vce. Current limit is applied to stop them blowing up. I can tuck tl3411 inside a E25 tp341 socket well immobile at the end of a hard wire. I would suggest that you put forth a full schematic, with the leds forward voltage and current specified. These results show a behavior that is similar to what you actually observed, including the relative behavior of the latter two cases where the current didn’t change much.
Here with each 2n Ib at uA, there is still 2. Let’s take your last case, since you had sufficient voltage then.
Not so, you absolutely need a higher Vce rating for your transistor. This is mains powered. Working out the resistors for the TL is very simple, consider this simplification from Figure 39 of the datasheet. You could also use a more capable power FET instead of a transistor, but this increases the complexity of the design in terms of minimum voltage etc.
So, the best was to try R1 values and that took me here, thanks for your answers. Component wires folded and 3 solder points, no need for soldering pads. Sign up or log in Sign up using Google.
Is this supposed to eventually be a mains-powered thing? I have bought LEDs corn cob lamps. The load can be inserted into either of the two locations shown, given that the other location is shorted when there is no load there.
Time to show a complete schematic for all three versions you are making. Consider that if you have 96 LEDs rl341 a Vf of 2. They are cleverly very simple: But the value of R1 is not clear and I found no simple howto on the Web.
The voltage above R1 is constant and tp341 or impacted by Vce for the transistor. Whatever the number of LEDs in the string, the only thing the circuit sees of it is a current.
tl – Configuring a TL current limitation – Electrical Engineering Stack Exchange
It only takes a few uA. Led currents do not need to be super accurate.
Just random remarks here and there plus 7. For the TL to work correctly, you need enough headroom. You state the you want to run 96 LEDs What do you think of that? Thanks for the only howto I saw, and a good one. Each string of LEDs is now only 12 devices instead of 14, but the voltage Vf difference for the string simply appears across the 2N But I think you are just testing this, for now, by shorting both of them. Sign up using Facebook. So I think this tells you one important fact — the TL is effectively “out of the circuit.
Now, this gets back to the question of how you intend to operate it eventually. The TL is featured in www. The current that they can handle is a function of temp. Let’s start with an overview schematic for the two simpler constant current topologies for the TL I’m using an SCR symbol for the TL here on the left side, below:.