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]
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]
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]
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]
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]
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]
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]
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]
This project is a Low Ohm meter able to measure 0.001 up to 1.999 Ohm with a “Direct Resistance Readout in Ohms”.
You must use two separate batteries. One for the DMM and one to supply power to the LM317LZ. I recommend the LM317LZ, which is the 100 mA, T0-92 version of the normal LM317. But you can also use the LM317, in the T0-220 package, if you want. The trimpot must be set precisely to deliver 100.0 mA out to get truly accurate resistance measurements. So you need a very accurate Milli-Amp Meter to adjust this Correctly.
Low Ohm Meter – Measures 0.001 up to 1.999 Ohm – [Link]
In this project we design low cost high performance programmable home security system using few LDR’s as an input sensors. When above sensor(s) get triggered system may dial the user specified phone number (using build-in DTMF generator) and activate the high power audio alarm and lights. All the parameters of DTMF generator, audio alarm and light interface are programmed through the RS232 serial interface.
Current firmware of this system presents interactive control system through the RS232 interface. This control system consist with the menu driven configuration options, self tests, system report generators, etc.
This system also contain 5W (with 4Ω speaker) audio alarm with three selectable tone configurations, which include Police siren, Fire engine siren and Ambulance siren.
This system uses a Microchip’s PIC16F877A as a main controller, LM339 as sensor interface, UM3561 as a tone generator and μPC2002 as a speaker driver (audio amplifier). LM7805, LM7812 and LM317 voltage regulators are used to obtain +5V, +12V and +3V respectively.
All the project source codes, schematic diagrams and PCB patterns are available in “http://elect.wikispaces.com/Programmable+Home+Security+Alarm+System” with terms and conditions of GNU GPL and Creative Commons – Attribution-ShareAlike 3.0 Unported license
Programmable Home Security Alarm System – [Link]