I built an rf single stage transistor rf oscillator, tank cct using 15 turns on a ferrite toroid, connected to collector, with a single turn coupling link to the base. Powered by a 12 v transformer supply. It takes a few flicks of the off/on switch to power up. (Mystery no 1). Then I replaced the power supply with a 12v car jump-start battery. Refuses to power up. I bypassed the off/on power switch, and tried applying 12v to the 12v power rail manually with a lead connected to the 12v car jump-starter, repeatedly pressing the 12v lead to the cct board 12v rail. Nothing. Incidentally, I had also placed a capacitor across the 12 V supply, which killed the oscillations immediately. Got rid of the capacitor. Still with the car jump-starter, I tried manually pressing the NEGATIVE lead to the cct board 0v rail, and after a few presses IT STARTED! Back with the original power supply, I placed a CRO across the power supply to see if there was some strange glitch in the 12v supply when I switched it on. IT WOULD NOT START with the cro connected across the 12V rails! I am mystified. I don't guess anyone here might have a clue about this. Seems there is something in the original power supply that is critical to oscillations starting up.
November 23, 2023
Also seems to depend on the manner of switching the power on.
November 23, 2023
No answers yet. Contribute your answer below!
Anyone can ask a question.
Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.
CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.
We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.
Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!
CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.
|New @ CircuitLab