The design of a variety of light control circuit
Abstract: This paper describes the effect of light source control circuit of the two transform the design and dance to the light gradient. Both control circuit design is, counting pulses generated by circuit 555 into the 12-bit binary counter, turn to the data stored in the EPROM read. Market share based on the actual applications and has proved that this circuit has a stable performance, long life, low cost (only every eight the cost 50-60 yuan), the circuit is simple, the advantages of short programming cycle, compared with the SCM has not incomparable advantages.
Keywords: gradient oscillation frequency hopping
As people’s living standards improve and speed up the construction of urban infrastructure, the use of light has long been not only used for lighting, lighting engineering in the city and a variety of large and small advertising signs in their talents.
1, eight-way light controller design flow
The controller’s main function is to complete the eight-way lights (including the bridge lights, fence lights and neon signs advertising a variety of large-scale) control. The controller circuit can be divided into 5V power supply, oscillator circuit 555, counter, program memory EPROM, SCR trigger current drive circuit.
Oscillator circuit shown in Figure 555, a pulse cycle high pulse width T1 = ln * (R1 R2) * C, low-level width T2 = ln * R2 * C, pulse period Tw = T1 T2.
Amplified by NPN-type transistor 9013 SCR trigger current. 9013 D saturation is high conduction current through the SCR’s T1, G the set of poles and 9013 to end the flow of the emitter; low end 9013, SCR off. To make 9013 work in the off state, the base limit resistor should not get too large, and generally 100 or 200 ohms. In order to reduce the load on 7805, 9013 collector supply VCC 9V output voltage from the transformer through the four diode bridge provides a whole, not by the 7805 provision, the collector current limiting resistor 100 in Europe, and its power consumption is P = (0.9 * V ) * (0.9 * V) / R = 0.64W, drive current I is 0.81A, V transformer output voltage 9V.
2, 7 neon color gradient controller design
7 The main principle is the color gradient, three-color mixing to achieve the changes 7 different colors, the gradient is applied in the output waveform of the pulse width modulation, that is, the duty cycle of conduction neon lights, in the case of fast scanning of the human eye using an inert to achieve gradient effects.
The power supply circuit, counter, program memory as the previous section. The performance of the SCR, even in the trigger voltage and current are changed to zero, and only the arrival of the alternating voltage is only off the solid output control switch with N-channel FET switch IRF460, also from the current drive driven to the voltage driver. As shown, when D is high, the 9013 saturated conduction, Vce is about zero volts, FET switch gate-source voltage is zero volts, FET switch off; when D is low, 9013 deadline, Vce voltage equal to VCC, FET switch gate-source voltage for VCC, then FET switch turns on.
Because the circuit output is DC, then the transformer can not be fixed inductor neon transformers, electronic transformers can only be connected.