A wireless bridge is a device that enables non-Wi-Fi devices to connect to wireless networks. But it does so in a way that ensures the original device still functions without access to the internet. It does not need any internet connection or even direct access to an available wireless network, which makes it ideal for use during blackouts, emergencies, or anywhere else you need reliable access to the internet.
A wireless bridge has two modes: client and access point (AP). The client mode is enabled by a network card that attaches to a Wi-Fi source, then converts it into a regular wired connection for an Ethernet port. A laptop with a regular wireless adapter could be set up as a wireless bridge with an external adapter. A wired device such as a computer, phone, tablet, or streaming box could be added as well if it has Wi-Fi capabilities. In access point mode, the device creates its signal that is then broadcasted for other devices to use.

How Are Wireless Bridges Useful?

Wireless bridges are useful for several reasons. First, there is no longer a need to set up multiple devices in inconvenient areas. If you need the internet on one end of your house, for example, and your router is at the other end along with all of your wireless devices like laptops and smartphones, then you can't connect anything to it via Wi-Fi. In that instance, you could set up a wireless bridge to bring the internet from one end of your house to the other end where you want it, and use the wireless devices as usual.
In another example, you could provide internet access anywhere in your office via a hotspot for any device to connect to. Just plug in a wired Ethernet connection at each networkable location and all those devices will now have connectivity. Wired connections are much faster than Wi-Fi and generally more reliable as well because there is no chance of dropping signal or interference from other networks nearby as often happens with public Wi-Fi such as those found in cafés, shops, and airports.

What Can Wireless Bridges Do?

Wireless bridges are good for many things, such as:
Providing internet access to those without home internet or devices. For example, you could set up a wireless bridge in your office and connect it to an Ethernet port so customers can check their email on their phone if the need arose.
Connecting two networks wirelessly. If your laptop is too far from the router and you don't have an extension cable available, then you could set up a wireless bridge between both of them for connectivity.
Expanding Wi-Fi coverage throughout homes or offices by offloading it onto another network not being used at the time. This is especially useful when using public Wi-Fi hotspots that are often crowded with many users trying to use it at once, resulting in connection problems.
Providing internet access anywhere. Once you have a wireless bridge set up with your regular devices, then you can take it with you wherever you go and have that same level of connectivity anywhere on the planet as long as there is a signal for your Wi-Fi adaptor to receive.

How Can I Use A Wireless Bridge?

Setting up a wireless bridge differs depending on the device itself. There are several models available at varying prices, but most share similar features and functions with some additional ones here and there depending on their capabilities. Most commonly though, they will be compatible with Ethernet connections via one or multiple network ports (Ethernet switches) or USB ports (if they are not built into the device itself), which are used to connect devices such as computers, laptops, phones, streaming boxes, tablets, printers, and more.
To set up a wireless bridge device properly with your network connection it is best to read the manufacturer's provided instructions on how to do so. The settings will also be located in the device manager on most operating systems which you can access by right-clicking the network adaptor of your choice (Ethernet or Wi-Fi) located under "Network Connections". If neither is available, then you could try calling your internet service provider for assistance.
An example of a wireless bridge is the TP-LINK TL-WR940N, which has 4 ports, allows for internet connectivity via Ethernet or Wi-Fi signal from your modem, and connects to virtually any device with an HDMI port or audio/video output. Another is the ASUS DSL-AC52U router which has one port but includes a USB 3.0 slot so you can connect larger files more quickly than most other USB 2.0 devices on the market today while also providing connectivity via Wi-Fi and Ethernet.
Another option would be this TP-LINK 8-port switch (Ethernet model) and power supply which allows up to 8 wired connections and comes complete with all necessary cables and adapters. This would allow you to connect many devices and run them all at the same time, just as if they were plugged into a main router/hub with multiple ports.
Also available are wireless adapters that convert an Ethernet cable connection into a Wi-Fi signal via a USB port for your laptop or computer. If you are interested in getting one of these then check out this list of USB wireless dongles compatible with Mac OS X or this list compatible with Windows. These can be very useful on the go when there is no space for a bigger device on your desk but still want to have internet access without wires since some laptops do not support Wi-Fi capabilities.