Today I has the 12Vdc to 9V DC converter step down voltage circuit come to advise, it uses easy. Because use the integrated circuit LM317T. Read next you will think to are like me
This little circuit uses a LM317 variable voltage regulator to adjust the input voltage down to [...]

If you need about 12,000 volts DC for an ion generator this circuit might be the ticket. It draws power from the 120vac power line but it uses a small 6KV camera flash trigger coil. The output signal is isolated from the power line. Although the circuit can only deliver about 5uA of current it [...]

When you lead to play MP3 or laptop computer come to apply to an automobile. Sometimes may born noise problem has from electricity automobile system. I thinks Power Filter Regulated for car by LM1084-12 may help solve a problem this get. .. [...]
Read More and View Circuit