LM317 Regulated 40V/2A Power Supply

Description: 

A very good and powerful Regulated Power Supply section was implemented by simply adding a PNP power transistor to the excellent LM317T adjustable regulator chip. In this way this circuit was able to deliver much more than the power required to drive two Mini-MosFet amplifiers to full output (at least 2Amp @ 40V into 4 Ohm load) without any appreciable effort...

Dual Output Voltage 5V/2A and 12V/2A with 2x7805 and 7812

Description: 

A friend of mine who runs an electronic shop wants to install an old cd-rom to be used as a stand alone cd-player in his truck. His problem was to find a suitable power supply for this purpose. A cd-rom uses 2 power supplies, 5 Volts which is used in its logic circuit and 12 Volts for its servos. With these parameters I needed to make a dual regulator that produces 5 Volts and 12 Volts output in one input voltage. Trucks usually uses 2 lead-acid batteries so that will be around 24 Volts...

3.3V Regulated Supply with 6V Input

Description: 

The figure shows the circuit, shamelessly copied off the datasheet provided by Microchip.

I have been more inventive with the parts. I had to get a modern P channel MOSFET from Texas Instruments because old hard drive boards were seriously deficient in this one critical component.

However, using the parts as specified would be necessary to get 1. A more compact layout 2. higher efficiency....

MCP73861 or MCP73863 USB Li-on Battery Charger

Description: 

This is a charger for lithium ion batteries which takes its power from the USB port of a computer.

It uses the MCP73861 or MCP73863 Li-ion battery charger chip manufactured by Microchip.