11-03-2021, 11:26 AM
(11-03-2021, 09:40 AM)Erik Josefsson Wrote: Meanwhile, can I ask about the HiFi headphone amplifier you used? This is a bit beyond where my learning curve ended when I studied (basic) circuits, but I wonder 1) if that amplifier would be powerful enough to pull a 35 gram neodym magnet (see picture) hanging in a spring into a forced oscillation? and 2) Do you think you could force a spring to oscillate with frequencies as a low as 1-2 Hz if you used phyphox's MULTI TONE GENERATOR (e.g. 440 and 441 Hz)? Obviously you would have to connect an iron core electromagnetic coil of reasonable size to the headphone amplifier instead of headphones. And be careful with distance etc.
Dear Erik,
I add a pdf file with all what I know about the amplifier. It is very useful when the generator has a high internal resistivity. But I do not think that it will work at 1-2 Hz, it is a sound amplifier.
You could use multi tone generator if you would add diodes and will keep only the envelope of the signal (4 diode bridge). Your resonance project is very useful and it would be great if it will work so using only smartphone with some minor addition. But I have not tried yet the forced oscillations of the spring with a mass. A headphone amplifier should be useful also to preamplify the smartphone signal before passing it to the diodes...
Best
Mikhail