LM7805

[AudioMime]

Hello, I have a few questions about the LM7805 and the schematic I'm using. I'm doing a circuit bend to this Casio PK-1 I got at goodwill for a few bucks, and I'm trying to add in a dc jack. I knew that 9volts would be too much, and so I was going to add in a a voltage regulator. I've seen the voltage regulators used in other schematics, and they usually have capacitors going from the input voltage and the output going to ground.

Do you think that 5volts would be enough? It should be, but I'm not sure.
Also, what value of capacitors do you think that I should use?

The schematic

[Fender3D]

3 points:

the circuit calls for 6V, you may add 2 series silicon diodes from GND pin to GND (anode to pin, cath. to GND); you'll have a 1.2V drop + 5V reg. = 6.2V.

Add another sil. diode from out pin to in pin (anode to out pin, cath. to in pin) for protection sake.

In circuit you have 470uF filter capacitor, your regulator out capacitor should be at least the same (greater is better), your in capacitor should be 4 to 10 times.

[amptramp]

There is a 7806 that will give you 6 volts out:

http://www.datasheetcatalog.org/datasheets/400/54086_DS.pdf

[timd]

Be careful not to add touch points if connecting to AC.

[AudioMime]

Alright, thanks guys! I think just using an lm7806 would just be easier

[Mark Hammer]

Doing a search on the OKI M6387-03 indicates that it shows up in many other casio keyboards, and is amenable to circuit-bending.  Is that your end-goal?