Panel switch wiring

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Thursday, November 13, 2014

12V fixed voltage power supply circuit diagram

Here this circuit diagram is for +12V regulated (fixed voltage) DC power supply. These power supply circuit diagram is ideal for an average current requirement of 1Amp. This circuit is based on IC LM7812. It is a 3-terminal (+ve) voltage regulator IC. It has short circuit protection , thermal overload protection. LM7812 IC is from LM78XX series. The LM78XX series IC is positive voltage regulator IC for different voltage requirements, for example LM7805 IC is made for 5 volt fixed output voltage . There is LM79XX IC series for negative voltage .

Circuit diagram of 12V fixed voltage power supply

A transformer(Tx=Primary 230 Volt, Secondary 12 Volt , 1Amp step down transformer) is used to covert 230V to 12V from mains. Here used a bridge rectifier made by four 1N4007 or 1N4003 diode to convert AC to DC . The filtering capacitor 1000uF,25V is used to reduce the ripple and get a smooth DC voltage. This circuit is very easy to build. For good performance input voltage should be greater than 12Volt in pin-1 of IC LM7812. Use a heat sink to IC LM7812 for safeguarding it from overheating.

Fig: 12V power supply circuit diagram

Wednesday, September 3, 2014

Fixed Voltage Power Supply

The fixed voltage power supply is useful in applications where an adjustable output is not required. This supply is simple, but very flexable as the voltage it outputs is dependant only on the regulator and transformer you choose. The maximum output current is 1.5A. Fixed Voltage Power Supply Circuits diagram : Parts : Part Total Description C1 1 2200uF 35V Electrolytic Capacitor C2, C4 2 0.1uF Ceramic Disc Capacitor C3 3 10uF 35V Electrolytic Capacitor

D1, D2 1 1N4007 Silicon Diode

BR1 1 2A 30V Bridge Rectifier

U1 1 Regulator (See Notes) T1 1 Transformer (See Notes) S1 1 SPST 2 Amp Switch F1 1 2A 250V Fuse and Holder Misc 1 Heatsink For U1, Line Cord, Case, Wire

Notes :

Since this project operates from 120 (or 220, or 240, etc.) volts AC, it MUST be built inside a case.
U1 will reauire a heatsink.
You will need to choose T1 and U1 to match the voltage you want. Use the table below as a reference.