Electronic energy-saving lamp circuit (2)

Compared with incandescent lamps, fluorescent lamps have the advantages of high luminous efficiency and no obvious temperature rise. However, when ordinary fluorescent lamps work,
they need to use a current insulator of corresponding specifications. When the ballast is operating, it will not only produce "buzzing, buzzing" noise but also
consume a considerable amount of electric energy. For example, a ballast equipped with a 40W fluorescent lamp consumes about sW of electricity at T. If
electronic circuits are used to replace ordinary ballasts, power consumption can be greatly reduced and the starting
performance of fluorescent lamps can also be improved.
    The circuit of this machine is similar to Example 287. The 20V alternating current is rectified by VDI-VD4 and outputs about 300v DC
voltage for the whole machine. Brother, island and VDII form a starting circuit to start the self-excited oscillator composed of VT1, VT2 and T
, and convert the 300v DC voltage into a high-frequency voltage of about 50kH, 270V, which is used as
the upper operating voltage of the fluorescent lamp F, c with j,. It forms a series resonant starting circuit. At (', a
high H of about 600V can be obtained at both ends to make the lamp E light up quickly.
    VT1 and VT2 use MTE13005 high-power tubes, Lu ≥ 30, and the characteristics of the two tubes are required Be consistent and install
a heat sink with sufficient area. The high-frequency transformer T needs to be homemade: use a high-frequency magnetic ring with an inner diameter ≠ 6 mm, and use
+0 0mrn high-strength polyester enameled wire to wind it,...L, 2 turns each, / . Wrap 8 pieces of wire around it. When installing, you should pay attention to
the first end of the coil and do not connect it wrongly. This circuit is suitable for 20-30W fluorescent lamps . When the circuit does not start,
the voltage at both ends of the lamp is about 600V. After
it starts , it will burn out.
The voltage at the tube_voltage terminal
is reduced to about 80V to maintain
stable and normal lighting of the lamp
.
    This circuit
can generally be successful after being powered on . If
the lamp current is inappropriate and
the light is brighter or darker, you can adjust
J.
The inductance reaches the appropriate value.