LM part, LM sell, LM buy, LM stock, LM datasheet, Semiconductor, Electronic Components,Buy electronic components,electronic parts. LM datasheet, LM pdf, LM data sheet, datasheet, data sheet, pdf, National Semiconductor, Voltage Regulator. Data Sheet. May File Number tle. -. M le l, h ra- al pli-. – s-. -. – li-. CAUTION: These devices are sensitive to electrostatic .

Author: Fenrilmaran Grosar
Country: Seychelles
Language: English (Spanish)
Genre: Medical
Published (Last): 20 October 2007
Pages: 387
PDF File Size: 20.99 Mb
ePub File Size: 15.87 Mb
ISBN: 520-2-80925-559-5
Downloads: 89833
Price: Free* [*Free Regsitration Required]
Uploader: Vuzuru

Still not enough, but far from as dztasheet as you estimated without helping resistor. What’s the purpose of the T1 plus Zener circuit? Otherwise, since adding guarantees is good in satasheet cases: Submitted by webmaster on 15 January Sign up using Facebook. Over voltage protection for the battery if someone adjusts VR1 too high?

Pin configuration Pin No. I can not use just a capacitor as a regulator, can I? Would you tell me from where the transistor’s base gets its negative voltage?

Sign up using Email and Password. The base of the transistor is connected directly to the regulated output of the transformer, so when the transformer produces 9 volts the base voltage will be greater than or equal to the emitter voltage and the transistor will open the circuit.


A capacitor is not a regulator. To use this IC for the different range of required output voltage, you can proceed with various circuits available in LM datasheet with having your needed output range. Ordinarily, I’d expect to see the LM wired as a current limiter, but in this circuit, is wired as an adjustable voltage regulator.

TL — Programmable Reference Voltage. For getting an output voltage range from 2v to 7v you can use the circuit below, which is a Basic Voltage Regulator circuit using LM voltage regulator IC. But when there is no power in the transformer, the output of the transformer is floating and the transistor’s base as well.

Sign up or log in Sign up using Google. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

How does this automatic emergency LED work? Or at least a voltage that is less than the emitter voltage by 0. You need a DC path for the base current. If those are 20 mA LEDs, you’ll want to be able deliver a total of about mA, so you’ll need a base current of at least 2.

transistors – How does this automatic emergency LED work? – Electrical Engineering Stack Exchange

It can able to provide a higher range of output voltage and current up to 10A by simply adding a series pass transistor with it, with having a wider range of operating temperature so the IC able to withstand for long.


I tried to find a path that connects any negative voltage to the base so that it closes the circuit and the LEDs turn l,724 but I didn’t find one! See the additional analysis above. Looks like it would pull daatasheet adjust to 0V if I understand it right.

LM724 PDF Datasheet Search Results

LM is an adjustable voltage regulator IC used for shunt regulator, current regulator, and temperature controller. Post as a guest Name. Yes, it seems to be a redundant voltage limiter that will kick in at about 7. Also able to use as either linear or switching type regulator.

I understand it but I have a question about the PNP transistor. PeterJ 16k 20 42 dstasheet This terminal is directly supplied from the supply when not connected to series pass transistor. Does that mean a voltage regulator must be used in automatic emergency led circuits? In actuality, to attempt at maintaining regulation, the LM will try to keep the original 1.

This circuit is very popular on the Internet.