I’ve always wondered what the heating system in these tablet and liquid mosquito repellents is like. When the faulty devices arrived, I had the opportunity to examine the liquid system. I also examined the intact tablet device. The liquid heating system in the “Raid Liquid Electric Mosquito Repellent” is strange.
I thought there was a resistor, a coil, or something similar. There’s a disc-shaped element placed between two metals, I think it’s ceramic-like. 220V AC is applied to the two metals, and the circular element resists and heats up. I measured it, and it showed a value of 2.6K, which I think is a different type of resistor.
To open the device, insert a flathead screwdriver into the slot as shown in the picture, release the tabs, pull back, and gently pull the sides. The rounded sections I’ve marked on the bottom are blind screws; the one on the right is welded, and they’ll break when you pull them. No problem, the tabs are holding them on tightly.
There’s no electronic circuitry inside the device. It contains a 1 amp 150°C thermal fuse (AUPO A8-1A-F), a neon lamp, and a 180K resistor. After the fuse, there’s nothing else, and 220VAC goes directly to the heating system.
Raid Mosquito Repeller Circuit Diagram
Since there was liquid involved, over time, I cleaned the oxidation from the parts that had contacted the disk, and the device worked flawlessly. The black cover on the first device was loose and came off easily, but the other one didn’t, so I had to break it.
Although, since the parts fit tightly into the slot and were compressed within the plastic casing, I thought there would be no problem. However, due to the high voltage, I didn’t take any risks and wouldn’t reassemble the device without finding and replacing the fireproof plastic part. By the way, you don’t need to remove the metal parts. Just pick up the round part with tweezers and clean the parts with a Q-tip.
So, one went for an inspection 🙂 The other was repaired.
While I’m at it, I also took apart the Raid tablet model. The 10-year-old device is sturdy and hasn’t broken down. I haven’t seen any breakages. The heating system is the same in the tablet model, but it’s more powerful, and since it’s not liquid, there’s no oxidation, so it doesn’t fail.
But there’s no thermal fuse; they just connected a 12-ohm 1W resistor in series with the 220VAC line. While I was calculating fireproof plastic for safety, they got carried away with this model. 😀
DİKKAT The mosquito repellent device operates with high voltage, so be careful. Before operating, use a fused power line and wear protective eyewear.
