Light-controlled street light circuit using MAX837

This circuit adopts 4-pin S (rr-1 43 package, the functions of each pin are:
① pin 6NI), ground terminal; ② pin
V... power supply terminal; ③ pin IN,
detection voltage input terminal; ④ pin
() UT , output terminal. The working voltage range
is 2.5~¨V. You can use M/XS37
to make a light-controlled automatic street light with extremely low power consumption
. See Ah 203 for the circuit.
The static power consumption meter is about 400tptA. 1
point energy saving, suitable for automatic control of street lights in private courtyards
, etc.
    The 2ZOV alternating current is rectified by VI)1~VD4, and one channel is directly added to the lamp E and the thyristor wr; the other channel
is passed through R. Reduce J soil current limit, VD5 isolation and vs voltage stabilization, and filter to obtain Sv DC voltage for MAXB37
power consumption. Rt, RL and RP form a light control circuit, R1 during the day. It shows low resistance when exposed to natural light. The input terminal II of MAX837, that is, the level of
pin ③ is lower than the valve voltage V,,, (1. 201V), so the output terminal OUT , that is, pin ④, inputs low level III, and VT has no trigger signal. , in the off state, the street light E does not light up.     When the sky gradually darkens, the RL resistance increases accordingly, causing the level of pin ③ of MAX837 to continue to rise. When the state reaches 120, iV, the cju'r end, that is, pin ④, outputs a high level, passing through R. Add it to the gate of VT to trigger it to turn on, and the street lamp E lights up. At the same time, this high level is isolated by diode VD6 and resistor R. It is fed back to the input terminal IN, which is the ③ pin, to slightly increase the level of ③ pin . The purpose is to avoid the flickering phenomenon C and the capacitor C connected between ③ pin and ground have anti- The interference absorption function can prevent the circuit from being falsely triggered by sudden strong light such as vehicle lights or lightning at night .     VT should use a micro-triggered one-way thyristor with a small trigger current, such as (0R02AM, which has a large on-state current of d0 3A. RT. It is an M(;45 type photoresistor, and the difference between the light resistance and dark resistance is required to be greater than The bigger, the better. The RP 30-meter adjustment circuit has light control sensitivity, and the wsW type organic solid core trimming resistor can be used. Other component parameters are shown in the figure, and there are special requirements for each other.