Excuse me why am I in this circuit when uln input output for the low levels is grey when sw1 to stir the relay power dial up again relay still keep current state
Using protues simulation

CodePudding user response:

Should be grounded ULN2003 OC output, the public end, rather than the VCC

CodePudding user response:

reference 1st floor zgl7903 response:

ULN2003 OC output, the public should be grounded, rather than the VCC

Why relay electrified no matter how to dial the switch in front of the relay is still not a bit

CodePudding user response:

Add
Optical coupling between no light at the CE is a high impedance state, 10 k pull-up is equivalent to the input driving up,
U3 directly connect the 12 v 4 feet, 1 Angle of U3 U1 3 feet, R3 on U3 3 between foot and ground, so that light coupling input light, UL2803 corresponds to lower, the output will shut off the

CodePudding user response:

Well, I try to thank you

CodePudding user response:

Haven't grounding ULN2003,