Review on URBEST HH52P Electromagnetic Power DYF08A by Mark Colbert

I am using a Hikvision DS-HD1 doorbell camera, I wanted it to sound a 12V buzzer in our loading dock. If you're like me and don't know anything about low voltage, Youtube isn't much help. Here are some useful points I would like to know: with a 16V (AC) transformer. This AC-DC stuff is immediately confusing. Second, you need two power supplies: I used a 24V AC transformer to power the doorbell camera and open/close the relay contact. I used a 16v AC transformer to complete the buzzer circuit. Third, I don't know how other doorbell cameras work, but I've found mine activates the contact (thus turning on the buzzer) for about 10 seconds before the power module finally opens the 24V circuit as and expected. When I originally tested I thought something was wrong with the relay, or more likely I wired it wrong. Finally, you have to select "electronic" call in the phone app. This allows you to set the duration of the beep (or chime). I've attached a photo of my masterpiece (hidden in the ceiling); and the other is a home made circuit that I found useful. This is for ring pros, but the same rules apply.