Rongge

Often, for certain low voltage lighting systems; you would like to turn off the lights during the bright light of the day.  Most commercial day/night switches are designed for AC lighting.  This hobby circuit below was designed for a 12v DC system.  But, it could be modified for other voltage as well.  It uses an inexpensive photo-transistor as the light detector.  An n-channel FET is used to switch power to the lights.  A transistor circuit is included to provide some hysteresis.   This keeps the circuit from fluttering the light during the transition from day to night and night to day.  It is recommended that a plastic tube be placed over the transistor to prevent it from being illuminated by the lights it is controlling.  By selecting the appropriate power FET, the circuit could control over 100 watts worth of 12v lighting.   (July 22, 2008) Source: DiscoverCircuits

This is a micro - inverter DC voltage to AC from a 12v battery can generate a voltage of 110 or 220 volts AC and a frequency of 50Hz to 60Hz . The circuit is very simple and does not need a printed circuit board , It is composed of two transistors oscillators that generate the square wave pulse to the transformer in the case is 10 +10 and its output 220V or 110V . This circuit is 50Hz , but can be changed by changing the value of RC .   Micro Inverter circuit DC voltage AC 12v x110v Circuit Diagram This circuit has the power transistor and that depends on the transformer .