Descrete Voltage Regulator for microcontroller

[dutchboy]

Hi all,

Thanks for taking the time to read this.

I have an Attiny45 programmed to flash some banks of leds, using transistors as switches, that are running off of a 9v PP3 battery supply and i also want to run the Attiny off of this supply. I had a look round and could use a LM7805 linear regulator but wondered if there was another option. I had a look at zener shunt regulators and that is an option but means i need to go and get another set of zeners(im lazy and always looking for alternatives!).

I was playing around in iCircuit on my iPad and came up with the schematic attached, i just wondered if any of you have used similar circuits or any reason why this circuit is a bad idea (i am a noob at electronics). The simulation seems to work well but it is just an iPad app.

The 2n2907 PNP is added to allow the regulator circuit more current, its possibly overkill but thought i would add it anyway.

I hope i have explained myself well enough.

Thanks,

Ian.

[digsys]

Problem with that circuit is - NO actual regulation. As the 9V battery drops, so too will the output !
Don't fool around, use an LM7805 or 7805L (up to 100mA) :-)

[fcb]

That 2907 looks useful..

Where exactly is the regulation?

[IvoS]

I think you could use a zener diode instead of 680 ohm resistor.

[dutchboy]

Great thanks for the replys will go with the 7805!! told you i was a noob!!! lol thanks all

[dutchboy]

@fcp apologies if I habe offended you in some way. I believed this was in the beginners part of the forum and therefore posted a question as a beginner in the hope of some guidance.