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LM317 is one of the most popular adjustable regulator chips. The output voltage of the regulator can be adjusted from 1.25V to 35V. However, the chip can deliver currents up to 1.5A which is not enough for some power applications. In this article/video, I will discuss two methods of LM317 current boosting, using power PNP and NPN pass transistors. References Article: https://www.pcbway.com/blog/technology/LM317_Current_Boosting_Secrets.html : LM317 Datasheet: http://www.ti.com/lit/ds/slvs044x/slvs044x.pdf : LM317 Library: https://componentsearchengine.com/part.php?partID=299235 : MJ2955 Datashet: https://www.mouser.com/datasheet/2/308/2n3055-d-1190033.pdf : MJ2955 Library: https://componentsearchengine.com/part.php?partID=697997 : 2N3055 Datahseet: https://www.onsemi.com/pub/Collateral/2N3055-D.PDF : 2N3055 Library: https://componentsearchengine.com/part.php?partID=788620 : CAD Plugins: https://www.samacsys.com/library-loader-help
Features: AC – DC Conversion Double output voltages (Positive – Ground – Negative) Adjustable positive and negative rails Just a Single-Output AC transformer Output noise (20MHz-BWL, no load): Around 1.12mVpp Low noise and stable outputs (ideal to power Opamps) Output Voltage: +/-1.25V to +/-25V Maximum output current: 300mA to 500mA Cheap and easy to solder (all component packages are DIP) A double output low noise power supply is an essential tool for any electronics enthusiast. There are many circumstances that a double-output power supply is necessary such as designing pre-amplifiers and powering OPAMPs. In this article, we are going to build a linear power supply that a user can adjust its positive and negative rails independently. Moreover, just an ordinary single-output AC transformer is used at the input. References Source: https://www.pcbway.com/blog/technology/Low_Noise_Adjustable_Linear_AC_DC_Power_Supply.html  LM317 Datasheet: http://www.ti.com/lit/ds/slvs044x/slvs044x.pdf  LM337 Datasheet: http://www.ti.com/lit/ds/symlink/lm137.pdf : Schematic Symbol and PCB Footprint for LM317: https://componentsearchengine.com/part.php?partID=248007 : Schematic Symbol and PCB Footprint for LM337: https://componentsearchengine.com/part.php?partID=290650 : Altium Plugin: https://www.samacsys.com/altium-designer-library-instructions