Touch desk lamp circuit

This is a human body sensor light. The light lights up when the human hand touches the metal part and stays on. It is also called "light on at one touch". When you want to turn off the light,
touch it again to turn it off, which is very convenient. Its appearance is as shown in
    the touch control principle. The frequency range of the electrical signal is from 0--5kHz, and the output voltage is from microvolt to millivolt level, which is a weak
voltage. Observed by the indicator, there are also various harmonic components. When a person touches the metal sheet M with his hand, it is equivalent to providing a signal to the VT base . After
current amplification, it is sent to the TWH8778 high-power drive switch integrated circuit , so that the NE555 ⑥ terminal is low level, and the ③ terminal is high level. The future
working status will be the same as before. Therefore, in daily use, it lights up when touched by hand, and can also be used as an alarm.