The first design is a simple 5V regulator. It uses only 3 components which are the regulator and 2 capacitors to smooth the supply. It is shown built on a piece of veroboard, but could equally be made by soldering the capacitors and leads directly to the regulator pins.
The second design allows the output voltage to be varied by changing the value of the included resistor. Again it can be built directly on the regulator, but it is a little more tricky. The regulation of this design is not as good as the unit above, but is more than sufficient for our needs.
Now to the tricky bit, the value of R. The equation for the value is Vout = Vreg + I'R. For the 7805 regulator the value of the I' parameter is approximately 4.5mA (0.0045A). Therefore R=(Vout - Vreg) / I' and the following table gives sample values.
| Desired Voltage (V) | Required Value of R (ohms) | Nearest Standard Resistor Value (ohms) | Approximate Output Voltage using Standard Resistor (V) |
| 5.5 | 111.1 | 110 | 5.50 |
| 6.0 | 222.2 | 220 | 5.99 |
| 6.5 | 333.3 | 330 | 6.49 |
| 7.0 | 444.4 | 430 | 6.94 |
| 7.5 | 555.6 | 560 | 7.52 |
Catatan :
Hal ini dapat diterapkan untuk membuat charger HP, IPOD, MP3, dll dengan media suplly Batere Motor atau mobil.
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