i have a following schematic for three-phase multivibrator:
SPICE simulation shows that it should work (11 volts peaks on collector nodes):
However, when i make this circuit on breadboard it does not work, only left and right LEDs are on, and no fluctuations occur. I have tried to google polyphase multivibrator circuits but non of them seem to work (i always use PN2222A). Is it PN2222A transistors fault? Thank you for help.
UPDATE 1 : As pointed out by Andy Aka i did make a wiring mistake (forgot to connect middle transistor's emitter to ground) . Circuit started to oscillate, however only left transistor visibly cuts off, middle is roughly half off, and right transistor only slightly dims. Ring oscillation is present.
Oscilloscope shows additional 600kHz oscillations at the collector of the right transistor.