Hey all
Firstly, apologies if the 2 questions in one post format is frowned upon here! I figured it was better then spamming new threads and as the old saying goes “it’s better to ask for forgiveness rather than for permission”
My first question is, is there a real quick and dirty way of working out if a transistor will work in a circuit for hobby situations?
I was searching online and found some fairly useful pages that list about 10 things you should compare and use a transistor with the same or “slightly higher” values. That makes perfect sense for professional work / stuff you want to actually put to work but can that be dumbed down even further for just hobby messing around (I.e. what are the most critical values and what is “slightly higher” - I.e. like max 20%)?
Specifically, I am looking to just build a little crapy FM receiver to feed into some audio amps and all the diagrams I have found seem to have obsolete / hard to find transistors listed. On the latest schematic asks for a few BF324’s. Using alltransistors.com to run an equivalency search brings up a whole bunch but the closest ones all seem to be obsolete / hard to come by too!
My second question is regarding creating (or more specifically grounding) a 0v rail. I had the idea of creating a variable positive and negative power supply using my 12VAC wall power supply (thank you so much again to everyone who recommended that to me previously! It has been a blast to play with!), a bridge rectifier, a LM317T and a LM337T.
However, after looking for schematics, I saw they were all connecting the 0v rail to the AC earth. As far as I understand, my AC power brick only has 2 prongs so doesn’t have an earth.
My question is, do I have to connect that 0v rail to earth by running a cable to the earth of a PowerPoint (or more realistically, via the earth pin on my proper lab bench power supply) or is there another way I can do it?
Please feel free to tell me I’m an idiot on this one
I tried researching it but came across a whole bunched of new terms from google such as “earth ground” vs “signal ground” vs “digital ground” vs “analog ground” and left more confused than when I started :p
It very well could be the case that I am just not ready for this project yet
Thanks so much in advance once again all