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7 Mar 2014


This project is a temperature controller for a PC FAN. It regulates the speed of the FAN attached to it according to measured temperature. Temperature is sensed using a simple NTC thermistor.

In most PCs the fan runs constantly, which may not be necessary. A simple circuit can regulate the fan speed according to temperature. This not only saves energy, it also reduces fan noise. Only three components are needed to allow the fan speed to be controlled according to the actual temperature: one adjustable voltage regulator (LM317T) and two resistors that form a voltage divider. One of the resistors is a NTC thermistor (temperature-sensitive resistor), while the other is a normal resistor.

Temperature Controlled PC FAN - [Link]

29 Dec 2013


by Aruna Rubasinghe:

The LM317T from National Semiconductor is a popular adjustable-voltage regulator that provides output voltages of 1.25 to 37V with maximum 1.5A current. You can adjust the output voltage with a potentiometer. The circuit in Figure 1 replaces the potentiometer with an analog voltage that you can control from a PWM (pulse-width-modulation) signal. You control this signal with a microcontroller or any other digital circuit. You can use the same microcontroller to dynamically monitor the output and adjust the LM317T.

Control an LM317T with a PWM signal - [Link]

24 May 2013


manekinen @ mdiy.pl builds a simple symmetrical power supply based on LM317 and LM337. Design is Eagle and includes PCB so you can build it your own.

This time, simple project that i made from simple need. Simple, cheap and functional regulated power supply 1,25V to 15V, two separately regulated positive lines and two negative. This power supply uses LM317 and LM337 integrated circuit stabilizers – or their stronger versions. Galvanically separated lines can be connected in various configurations.

1.25V to 15V Simple Dual Symmetrical Power Supply - [Link]

15 Mar 2012

This power supply uses the integrated circuit LM317T, which allows to vary the output voltage from 1.2 to 30V with currents of up to 1.5 Amperes.

LM317 Regulated power supply 1.2 to 30V @ 1.5A - [Link]

15 Mar 2012

Radu Motisan  writes:

Having a regulated power supply that can output precise voltages in the 0 .. 30Volts interval is a great add-on for any electronics lab. Especially when it’s a high power supply.

For this article, I’m going to show my supply, built from scratch, the design I’ve used (schematics) and a few safety tips.

First thing we need is a high power transformer. I’ve ordered a custom toroidal unit, with a primary for 220V mains, and two secondaries one of 24Volts, 10Amps max and another one of 12V, 0.5Amps max. It’s very heavy it it was quite expensive. I’ve also purchased a rectifier bridge, capable of handling 400V at 35A max.

Variable 0..30V 20A Regulated Power supply using LM317 - [Link]

22 Nov 2011

jumperone.com writes:

How to build your own linear adjustable power supply based on LM317. In this tutorial I’ll explain how linear power supply works, what parts it consists of and a lot of small details, like how to calculate smoothing capacitor value, or how to choose a transformer. Plus you’ll see how to build an actual power supply.

LM317 Simple Adjustable Linear Power Supply - [Link]

14 Sep 2011


Simple Linear Adjustable Power Supply Tutorial (Based Around LM317) by JumperOneTV… – [via]

Adjustable LM317-based power supplies are an easy way to get custom voltages for your benchtop. Also check out the MIC2941 which has some nice benefits such as ultra-low dropout, 1.25A current output and a separate biasing pin. Its nearly a drop in replacement for the LM317 – albeit a little more expensive.

Simple Linear Adjustable Power Supply Tutorial - [Link]

22 Mar 2011

This is a very low cost and simple Arduino GSM and GPRS shield. We use the module SIMCom SIM900. It’s the cheaper module now avalaible in the market.

To connect this module to Arduino I make a PCB that include a LM317 some capacitor filter and no more. I performed a GSM library to controll easly the module. The GSM library is a modified version of the library of HWKitchen.

With our version we controll the module throw the pin 4 and 5 (so normal digital pin) and our GSM libray include also the NewSoftSerial, so you can easy control the module, send and read SMS, make call, control the GSM state ecc.

To download schematics, PCB and Library check the site.

Arduino GSM shield – [Link]


5 Mar 2011

The circuit can be used to charge 12V lead acid batteries.

Pin 1 of the LM317 IC is the control pin which is used to control the charging voltage, Pin 2 is the output at which the charging voltage appears, Pin 3 is the input to which the regulated DC supply is given.

Battery Charger Circuit – [Link]

10 Feb 2011

Here is a simple and economical 10A variable power supply with 1.2-30V. LM317 have been used to drive 3 NPN TIP41C transistors (or three 2N3055). Nothing to say about the project, it is really simple. The main supply must be connected to a rectified source (transformer + 20-30A bridge rectifier). For Q1,2 and 3 can be used any power TO220 transistor (TIP132C,TIP41C etc) or three external 2N3055 transistors. [via]

10A 1-30V Variable Power Supply with LM317 - [Link]





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