Using electronic diagram below can be made very simple sinusoidal signal generator using very cheap electronic components. This sinusoidal signal generator output voltage is relatively stable (at a level of about 4.5 Vvv).
With component values of C1 (C1 ') and R1 (R1), the output frequency will be about 300 Hz. Frequency can be modified by replacing it R1 and R1 'with a double potentiometer. To maintain frequency control between the limits, the entire field of variation of the potentiometer should not exceed: a decade.
This scheme is a simple circuit for electronic autodisconnect lighting. This autodisconnect lighting circuit is based of known type 7555 CMOS timer connected as monostable. The component values from this circuit diagram introduces a delay of about five minutes before the light goes off. If you want to change this delay time can be modified components R1 and C1 values as t = 0.69 xR1xC1 [seconds] where R1 is in ohms and C1 in farads. Resistors R2 and R3 are designed to hold extra trigger inputs, the reset sensors that are used to trigger monostable or reset before the delay time elapses.