Hi all,
Recently I decided to dabble in home automation, so I built a mains switch controllable over WiFi.
It worked great for an electric kettle and a (presumably - it wasn't mine) incandescent lamp.
However, today when I was trying to set up some crude current monitoring, I noticed a weird problem with the LED table lamp I plugged in.
Even with the relay control input completely disconnected, the lamp would briefly and dimly flash, about once per second.
First I suspected a faulty relay, so I pulled out another one and connected the AC terminals in the same way, with nothing on the control input. The same phenomenon occurred.
I connected my scope to the AC output terminal of the relay, and instead of showing zero volts like it's supposed to, I saw a 40V, 50Hz AC signal which over the duration of 1 second increased to about 85V, causing the lamp to flash and dropping back to 40V. The shape was not sinusoidal but more like a trapezium shape, distinctly clipped at the top and bottom.
The relay is a Fotek SSR-25, supplied from 230VAC.
I'm just wondering if anyone has any idea what might be causing this, or if they've encountered the same thing?
Recently I decided to dabble in home automation, so I built a mains switch controllable over WiFi.
It worked great for an electric kettle and a (presumably - it wasn't mine) incandescent lamp.
However, today when I was trying to set up some crude current monitoring, I noticed a weird problem with the LED table lamp I plugged in.
Even with the relay control input completely disconnected, the lamp would briefly and dimly flash, about once per second.
First I suspected a faulty relay, so I pulled out another one and connected the AC terminals in the same way, with nothing on the control input. The same phenomenon occurred.
I connected my scope to the AC output terminal of the relay, and instead of showing zero volts like it's supposed to, I saw a 40V, 50Hz AC signal which over the duration of 1 second increased to about 85V, causing the lamp to flash and dropping back to 40V. The shape was not sinusoidal but more like a trapezium shape, distinctly clipped at the top and bottom.
The relay is a Fotek SSR-25, supplied from 230VAC.
I'm just wondering if anyone has any idea what might be causing this, or if they've encountered the same thing?