Infrared remote control light switch circuit (1)

The infrared remote control light switch uses Hj infrared light as a remote control command. It has the characteristics of strong anti-interference ability and reliable action
. The switch consists of an infrared light transmitter and an infrared light receiver. The circuit for infrared light emission
is shown in Figure 211(a). As can be seen from the figure, diodes VT1 and VT2 form an astable multivibrator. The oscillation frequency is determined by (1., Rt, C" and R. When the transmitter switch SB is pressed, the circuit starts to oscillate immediately, and is connected in series to the collector of
VT2
The infrared light-emitting diode I_ED of the loop emits an external light pulse controlled by the oscillation frequency,
causing the receiver to operate.
    The circuit of the infrared light receiver is shown in Figure 211 (b), which consists of a photoelectric sensor, an amplifier, and a dual It is composed of a steady-state trigger
and a power circuit.
    The light sensor is mainly driven by the photosensitive transistor VTP. It receives the infrared light pulse from the transmitter and
converts it into a corresponding electrical signal. Through the three-digit direct coupling VT1-Wl3 After amplification by the type amplifier, (1., VI)l is shaped by
(2) and added to the bistable flip-flop composed of VTd and VT5, causing the state of the bistable circuit to flip.
The electronic switch tube VT6 is forced to turn on and off The state is changed, so that the relay K is attracted or released, so that
the electric lamp E can be turned on or off remotely.
    In the transmitter, VT1 and VT2 should use silicon NPN transistors such as the 9014 type that are as consistent as possible. , p
≥ 100. LED can use H(;401, H(500 type and other infrared light-emitting diode). RP is used to change the infrared light emission
intensity and can shorten the distance. In order to reduce the size of the emitter, G can use 6F22 type 9V Layer program battery.
    In the receiver, VTP uses 3DU5 type photosensitive transistors. VT1-VT6 all require p ≥ 100. Among them,
the p value of VT5 is required to be larger than VT4. The purpose is to make VT5 saturate and conduct first when the receiver is first powered on. , wr4
is cut off, then VT6 is cut off, and relay K release is in standby state. VD1 needs to use 1N6, /AP9 type
and other germanium detector diodes. RPI is used to adjust the receiving sensitivity, the maximum receiving distance can be up to 8m. RP2 collapse to
adjust The working current of the relay. For the JRX-1:lF small relay with a DC working voltage of 12V, adjust
RP2 so that the pull-in current is 20mA. T can use a 220V, /12V, 5VA small high-quality power transformer.
    The transmitter and receiver The casing can be made of organic glass. The infrared luminescent tube and photosensitive transistor should be less exposed to the casing.
In order to prevent stray light interference and improve the appearance, it is best to use red glass to block the outside.