I have an WiFi router which I have connected to the inverter line.When ever electricity does sometimes it handles the switch over from mains to inverter and vice-versa, but sometime when the switch over time is slightly more it switches off and I need to manually on it.Is there any thing available which can give me a 10-15 seconds backup so that router should not switches off when it is getting switched from mains to inverter or vice-versa?I know UPS is an answer but I do not want to invest that much, a small device with capacitors for few seconds backup is sufficient.Please let me know if you have heard of this kind of device.