The 2-inch device, dubbed Chromecast, is aimed at replacing set-top boxes and can be controlled by both Android and Apple smartphones or computers. Google said it will also stream music or even show Web pages from computers using the Google Chrome Web browser.
Analysts said the device could be a disruptive move by Google to compete with Apple and other tech companies that want to bring Internet services to the television set. Forrester analyst Sarah Rotman Epps tweeted that it represents a "smaller, more elegant approach" compared with Google's previously halting efforts at similar products.
Google announced the device at an event where the search giant also showed off a new Nexus 7 mini-tablet with a high-definition screen that the company said is especially suited for high-speed gaming and video streaming.
Other announcements included an update to the Android Jelly Bean operating system and new tools for developers to build high-definition games for tablets. Google also announced it's expanding its online books business by selling college textbooks from some of the country's biggest publishers.
But the star of the event was the new Chromecast gadget, which looks something like a USB memory stick but packs far more capabilities. When plugged into a TV set, Google said the gadget will connect both to a home wireless router and to other devices such as smartphones, tablets or laptop computers. Anyone in range can then use their smartphone or computer as the "remote control" -- to select a video from YouTube or Netflix, for example.
The Chromecast takes its cue from the selected device but then streams the video or other material directly from the Internet, through the home router, so the smartphone's battery doesn't drain, Google representatives said.
Google executive Sundar Pichai said the gadget was inspired by the observation that, "It's very, very nice to show videos to your friends, but it's really difficult to do" on the small screen of a smartphone.
The device won't work with videos from Amazon or Hulu unless the material is being streamed from a laptop using the Chrome browser. Pichai said Google is talking with a variety of companies about creating apps that would work with Chromecast. "I fully expect a lot more partners to join us," he said. Pichai is Google's senior vice president over both Android and Chrome software, and the company touted both at Wednesday's event.
Google's new Nexus 7 tablet, which runs on the newest version of Android, sells at $229 for a 16-gigabyte model that works with Wi-Fi, and $329 for a 32-gigabyte version that works with all three wireless carriers: Verizon, AT&T and T-Mobile. That's significantly less than Apple's 8-inch iPad mini, which starts at $329 for a 16-gigabyte model without a wireless plan, but more than the cost of Amazon's Kindle Fire, which starts at $159.
Google usually uses the Nexus brand of smartphones and tablets to show off the latest features of its Android operating system, and to set a standard that it hopes will attract other manufacturers and consumers.
While the company doesn't make much money from selling the devices, or from the Android software itself, they are part of a strategy aimed at getting consumers to use Google's other online services -- such as search and maps -- which are major sources of advertising revenue for the company.
Android is now the most widely used operating system for both smartphones and tablets in the world. More than 56 percent of all tablets sold in the first quarter of 2013 ran on Android, according to the research firm IDC, while slightly less than 40 percent were iPads, which use Apple's rival iOS software.