Various aspects of home brew inverters

Author	Message
Tinker Guru Joined: 07/11/2007 Location: Australia Posts: 1904	Posted: 11:04pm 04 Nov 2017         oztules said   The 4uf I was referring to is the 4u7 on the rectified side of the little tranny. I know you wanted to be different, but if you look at my board, it has two decoupling and filtering parts to it. First it is rectified, then it goes through 7k5 resistor, then it goes through the trimmer, which is 1k8 from ground, and the trimmer is 500r. It then has 4u7 across the output of the trimmer.... to ground...so stage 1 low pass filtering and decoupling is achieved, then it goes through another resistor, and to the VFB pin as well as another decoupling/filter cap of small capacitance to chop off the HF ripple that may be there. ........oztules Thanks oztules, for clearing that up. Somehow I missed that 4u7 when I reverse engineered your PCB to see what makes it tick. Unfortunately the "no circuit diagrams" comment left me with no choice... Anyway, I have everything else you mentioned duplicated on my VFB circuit and its a simple task to replace my 0.1uf cap used at the first stage with a 4u7 cap. The 100R resistor from pot wiper to pin 13 & 0.1uF to ground is already there. I will check tomorrow if that made that 50mV hash disappear. The inverter is still waiting for the LCD combination power display module/meter to arrive. I had bad luck with the 4 display LED ones you show on your pics, two of them had lost a segment or two from the 7 seg LED's. Looking inside I found solder globules shorting tracks... They did work for a while though. Inverter update with final pictures coming soon... Klaus