Order Number LMCT. LMCT or LMCT. See NS Package Number T03B. C National Semiconductor Corporation. RRD-B30M Printed in. Semiconductors – IC – Integrated circuits – Power Management – Stabilizers FIX. Image: Click to enlarge. SOT23*LM National Semiconductor => TI. Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright , Texas Instruments Incorporated.

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Like Russell says, you can protect the output against overvoltage by placing a power diode between output and input, cathode to the input.

Using an LM in this manner is much better – it is designed to be used like this. Cool Projects for Open Source Hardware. It is a component in switching regulator designs and is not a linear regulator like other 78xx devices.

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The 78xx family is commonly used in electronic circuits requiring a regulated power supply due to their ease-of-use and low cost. Articles needing additional references from January All articles needing additional references. I think you answered part of your own question: From Wikipedia, the free encyclopedia. The LM78S40 from Fairchild is not part of the 78xx family and does not use the same design. Retrieved from ” https: These devices support an input voltage anywhere from around 2.

How can this give 15 Volt output? That’s right, the standard linear regulator since many moons. Reports of the death of the may be premature: It can withstand a reverse voltage of V, while the 50V of the 1N will do nicely.


Is this design around correct?

It is said to be a regulated power supply with variable DC output V, mA. But we don’t know its value so we are unable to say what will be the exact output voltage when using the design on the first image.

Good news for China btw: Some devices provide slightly different voltages than usual, such as the LM78L62 6. The SR from Datel is a full switching power supply module designed as a drop-in replacement for 78xx chipsand not a linear regulator like the 78xx ICs. The 1N for the rectifier is overkill. My life will never be the same again: OlinLathrop don’t forget s and s Sign up or log in Sign up using Google.

Isn’t LM generally more suitable for adjustable voltage supplies of this kind than ? I expect there actually is some resistor insideso R1 is not required smeiconductor let it work.

The seems to me like a LM with those R1 and R2 added inside. Encyclopedia of Electronic Components Volume 1: Views Read Edit View history.

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Ground is connected to your mains! My second smiconductor goes here: Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. Wow, when did LM become obsolete?

Wikimedia Commons has media related to 78xx Series and Voltage regulator circuits. This page was last edited on 5 Decemberat And my third question: This means your regulator won’t go higher than January Learn how and when to remove this template message. Fig 5 in the datasheet is the same effectively as above but the reference voltage is 1.



Possibly lethal, but you may survive it The variable resistor to regulate the output voltage. Then I am confused about voltages. For the years, see 8th millennium. Also, LM has got a lower dropout voltage than and can give a higher current.

You’ll be able to regulate from 1. What I miss there is R1. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. You’re right about the voltage drops, though I would calculate with 1V per diode. Notice that this circuit is not isolated from the AC line! To protect against the back polarity problem that you mentioned, connect a diode from output to input usually non conducting.

Email Required, but never shown. The circuit is wrong. A can be used in an adjustable mode as per the diagram you semicohductor – using R1 semiconduuctor R2, BUT it is not a good regulator to use this way as it draws substantial and variable current via its adj ground usually pin which leads to poor regulation.

So we’ve got only 8.