You want something like this
The above product is merely representative, and is not explicitly endorsed, nor has it been used, by me; but it illustrates the concept you want.
Such may be cheaper elsewhere, and there may be better ones out there. Be aware, though, of component to HDMI, which solves the opposite problem, and that simple passive HDMI-to-component cables (while cheap) work only with systems expecting them. HDMI is not intrinsically backward compatible without an active conversion box, though specific devices may use the HDMI connector to supply analog signals; just because their designers are cheap.
(Actually, I apologize, the product linked above specifically notes that it does not support HDCP-encrypted HDMI, which is most HDMI. Unfortunately, this is a product category where skeezy fleabay dealers, like, say this one are more likely to have the goods. HDMI, is supposed to be all, y'know, super-encrypted and Safe For Premium Content and whatnot, thanks to HDCP. Unfortunately, that means that Good Upstanding Merchants tend not to carry certain useful HDMI-compatibility adapters. Monoprice, for one, dropped their inventory. Google still remembers; but they deny it now. Since HDCP is good and broken, the goods exist; but you won't find them, at least not labelled honestly, on the shelves of the respectable. Sort of like Macrovision strippers back in the day.)