555 telephone desk lamp circuit As shown in Figure IC2 and R3, CI forms a monostable delay circuit with a delay time of T = 1.1R3C1 = 110s. Telephone function: When a call comes in, the telephone ring tone signal transmitted by the outside line of the telephone passes through VDI~VD4. After the bridge rectifier circuit is rectified, it becomes a DC signal voltage. This DC signal turns VT through a photocoupler ICI. After VT is turned on, the collector voltage is lowered. This low voltage triggers the monostable circuit to be flipped by the 2-pin. The monostable circuit outputs a high level. The triac VS is triggered to turn on through R4 and the LED, and the light is on. After the lamp is turned on, the monostable circuit enters the delay process, and the delay time is 110s. After 110s, the monostable circuit delays to return to the steady state, and the lamp is extinguished. According to the needs of different office environments, office projectors are roughly divided into three categories. 4k meeting room projector,video projector for meeting room,good projector for meeting room,conference room led projector,lcd meeting room projector Shenzhen Happybate Trading Co.,LTD , https://www.happybateprojector.com
One is a conventional projector that is placed or hoisted in the conference room, the second is a Portable Projector that can be carried around, and the third is an ultra-short-throw projector for convenient work reports and speeches.
With the advent of the Internet era, the emergence of wireless office series represented by ViewSonic PJD6352, PJD6550LW, PJD6252L, and PJD6552LWS has added new members to the office projectors. The wireless Office Projector is realized by the built-in wireless module of the ordinary office projector. Wireless office enables people not to switch signal lines frequently during office meetings, allowing people to have a better experience in meetings.