Hi all First let me say I am happy to be here and I hope that I am able to contribute.
I am hoping however that someone can help me out as I feel rather stupid I am attempting to change a 12v dc regulator from outputing 4.5v to 3v it is based off of a MC34063A IC the problem I have is this as it sets the sense resistor is 0.39ohm, R1 is 1kohm, and R2 is using 2 resistors in series that equal out to 3.7k Ohm. I am using this calculator http://www.nomad.ee/micros/mc34063a/ which is rather close at 4.5v to how it is currently configured. The problem starts when I attempt to change R2 to the 1.8kohm that is says for R2 the output drops to 0v. I am rather confused at this point. I am attaching a photo of what I am working with.
Thanks,
Yonubear