LED flashes twice a second
Capacitor and resistor values variation will change the frequency.
Supply voltage influence frequency of operation.
A BC337 can replace 2N2222A; voltage can be 9V.
Second circuit work directly off the mains 110V or 220V,
110V AC Resistor = 47K.
Using in second circuit BC337, resistor is 390K for a 220V and 180K for a 110V.