Infrared remote control a dimming circuit

  
(1) infrared transmitter circuit of the infrared transmitter circuit shown in Figure 18-la. By transistors VT1, VT2 and RC components and the like more than a flop. Multivibrator works; Kun brother were VT2, VT1 base bias resistors, closing the switch SA plus
Infrared remote control a dimming circuit - schematic

power supply voltage is, VTZ priority conduction, the collector electrode was low Tun "O", this low level by VD2, C3 is coupled to the base of VT1, VT1 cut so stop. After VT2 conduction, R4, VD2 and VT charge to G, the charge is to make the C band left and right positive negative charge, so that the base of VT1 potential begins to rise. When the base voltage rises to a certain value, VT1 conduction, the collector under variable level jump through VDI, the island was added to the VT2 base, so that VT2 by conduction to cutoff. After a short while, rr, 1 turned off, VT2 conduction. vri, VT2 alternately turned on and off, so to the cycle continues. So called astable multivibrator. The oscillation frequency depends on the charge and discharge time constant R, G, and Ra, the island. VT1, VT2 after the start-up alternately turned on and off, then on its collector LED2, LED3 and LED1 alternately emit infrared light red shade. LED visible light is used to monitor the oscillator is working properly or not, that is the working condition. (2) When the infrared receiver circuit infrared receiver receives the remote control signal emitted by the transmitter, after KA2184 processed by pin output low. This added directly to the VT low base, it is turned on, its collector current output secluded island formed a high-level output end of the. This was added to a high level by withered optical circuit LS7232 auxiliary input ( feet). As the dimming control signal. Reception circuit shown in FIG. 18-lb, it is an infrared remote control dimmer circuit, when its trigger input pin, feet it will be a continuous control of the control pulse output TRIAC conduction angle, so that the TRIAC conduction angle 41. -160. Changes between. With bidirectional thyristor. Tube conduction angle changes, the lamp becomes bright or dark by the light dimmed, thus realizing the lamp dimming control. In the dimming process when required by the dark to bright lights, press and hold the button on the remote control transmitter continuously transmits a control signal. Then you can see the lights gradually brighten, when it reaches the desired brightness, immediately release the PTT button, then the brightness of the lamp will stay in this position. If even continued the next, from the bright lights will gradually darken until extinguished.. Note: LS7232 is a PMOS type IC, so its power polarity with conventional CMOS circuits to move the anti-that it should be connected to the negative terminal Vm power supply, while the positive end of the rainbow should be connected to the power supply. The circuit power is still using AC power supply, capacitance G buck, rectifier diode VD1 half crossing. And other different capacitor step-down power supply circuit is that the power of the buck capacitor in parallel with a G 220vH inductance, its role is to absorb harmonics generated by the LS7232, prevent its interference with other appliances through power line .




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