Simple Split Power Supply 9V

Simple Split Power Supply 9V circuit diagram

This is a simple circuit design of 9V split power supply. This power supply circuit delivers plus and minus 9V to substitute the two 9V batteries. The rectifier circuit is certainly two separate full-wave rectifiers fed from the secondary of the transformer. One full-wave rectifier consists of diodes Dl and D2, which produce +9 V, and then the other consists of D3 and 4, which produce -9 V.

Every single diode from every pair rectifies 6.3 VAC, half the secondary voltage, and charges the concerned  filter capacitor to the peak value of the AC waveform, 6.3 x 1.414 = 8.9 V. Every single diode ought to have a Peak Inverse Voltage (PIV), rating which is at least twice the peak voltage from the transformer, 2x8.9=18 V. The 1N4001 features a PIV of 50V.

The transformer type is step down transformer with input / primary of 120V. You should be replace the transformer if your home electrical installation is use 220V.

About Power Supply
A power supply is a device that supplies electrical energy to one or more electric loads. The term of "power supply" is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy (e.g., mechanical, chemical, solar) to electrical energy.
A power supply may be implemented as a discrete, stand-alone device or as an integral device that is hardwired to its load. In the latter case, for example, low voltage DC power supplies are commonly integrated with their loads in devices such as computers and household electronics. More explanation about power supply can be found at

This is the tutorial about "How to build an AC to DC power supply ". The video tutorial covers the basics of diodes, bridge rectifiers, and how to build simple unregulated AC to DC power supplies than can handle a few mA up to several Amps.

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