Simple light-controlled street light circuit (4)

It is a light-controlled street light circuit made of general thyristors . And it also adopts the two-wire connection method,
so the installation is relatively simple.
    During the day, the photoresistor R1_ is exposed to natural light. RT. It shows low resistance, and after dividing the voltage with R,
the obtained voltage is lower than the reversal voltage of the directional trigger diode VDH, the rectangular thyristor VTH is disconnected, and the voltage
E does not light up. When night falls, the voltage on RI gradually increases. When it is higher than the switching voltage of VDH,
VT11 is turned on and the street lamp F lights up. This circuit also has a soft start process, which is beneficial to extending the service life of the bulb
. Increasing or decreasing the resistance of R can change the light control sensitivity of the circuit , but generally there is no need to adjust it.
    VDH can use bidirectional trigger diodes with a folding voltage of 26-40V, such as 2CTS, DH3 type, etc.
VTH can use 3A/600V thyristors. When
a radiator with sufficient area is installed, the maximum load power is less
than 500w.