The secondary of the transformer T has an AC voltage of about 70V, which is rectified by D1 and Cl, and then regulated by Rl and DWl to obtain a voltage of VDD=+12v. After power on, C2 charges DW2, DW3, RP3, R3, after charging to 2∕3VDD threshold level, 555 reset, Jl pulls in, J1-1 disconnects, CJl disconnects, due to the current limiting effect of C0, Power saving at no load, the primary current is only about 300mA; when soldering, the secondary voltage of T is only 30-40V, the voltage drops rapidly, causing the 555's 2 pin level to be lower than 1∕3VDD, 555 set, J1 Release, CJ1 is closed and the welder is welded at full pressure. When welding, due to the low voltage, DW2, DW3 is less than a thousand is broken, maintaining the steady state of 555. After the torch is put down, the voltage is raised to about 70V, the 555 is reset, and the CJl is disconnected and in a power-saving state.
The photoelectric switch is the abbreviation of the photoelectric proximity switch. It utilizes the shielding or reflection of the light beam by the detected object, and the circuit is connected by the synchronization loop to detect the presence of the object. The object is not limited to metal, all objects that can reflect light (or block light) can be detected.
Photoelectric Proximity Sensor,Photoelectric Switch Sensor,Photoelectric Proximity Switch,Infrared Photoelectric Switch Sensor
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