high frequencies

very high frequencies

very low frequencies

audio frequencies

no stable state

one stable state

two stable state

either one or two stable states

3 to 10 volts d.c.

1 to 5 volts d.c.

-5 to +5 volts d.c.

+5 to +15 volts d.c.

sine wave oscillator

square wave oscillator

saw-tooth wave oscillator

none of the stated above

Schmmitt trigger

blocking oscillator

multivibrator

Weinbridge oscillator