tv and passive speakers


 first I apollogize   for this very long post. this is a suggested solution for those who would like to add passive, as in non powered, speakers to a flat screen tv, smart or not smart. typically flat screens have multiple inputs and outputs connectors of various types all selected via the included remote. since this is for speakers I will ignore the inputs.
the tv will typically have one or more audio outputs either RCA or 3.5mm (1/8) stereo jacks, one or more. this jack is NOT powerful enough to drive passive speakers or even a headphone. in the case of speakers there are 2 solutions. I suggest a pair of computer POWERED speakers with 1/8 stereo plug. if you want seperate volume control, as in l/r, you will need to discard the un powered speakers, make your own "Y", consisting of a stereo plug and two stereo or two mono jacks. these are wired plug tip to jack tip AND plug ring to jack tip. BOTH active speakers use the TIP as the input.
a second alternative which I used was to add a small MONO amp to a small speaker enclosure and turn the speaker from passive to active. the amp will be in the 5 watt range using either 1/8 mono jack, coax connectors,  screw terminals or a combination of both. all connections are well marked. the amp has an onboard volume which may or may not contain a power switch. there are 3 connections to be made for each amp, dc power in the 3 to 24 volt dc range, an audio input signal, and an audio output to the speaker terminals. in addition a "Y" is again needed. this time consisting of 3 1/8 stereo plugs, or 1 stereo plugs and 2 mono plugs. they are wired plug tip to plug tip AND plug ring to plug tip. the amp uses the jack tip as the input. the difference between computer speakers and these amps is a plug versus a jack. both use the TIP as the input. the "Y" needs to be wired accordingly. screw terminal jacks/plugs are ideal. NO soldering.
the bottom line is that the tv audio out jack will NOT drive passive speakers! as for headphone it may or may not. if not simply add a small headphone amp to this jack. the amp may be 5 volt powered in which case you can use the tv usb port for power or use the included power supply. or it may need a 12 volt supply.
if you want to use BOTH the phone and speakers at the same time, again a STERO "Y" is needed with a PLUG to the appropriate jack/plug combination to mate with the speaker amp regardless of which speakers you are using. AND the headphone amps INPUT. have fun experimenting and learning along the way!
rtrg
There has not been many TV's that could drive out board speakers. none in the last decade or 2 I'm betting. 

 The 1/8 jack ( unless labeled headphone and only on very small TV's) or RCA out jacks are LINE LEVEL always have been so yeah you need a amp between the unpowered speakers and TV. 

get a sound bar. 

cheep used AV receiver to go between your TV and speakers. That gives you everything you may need for balance volume etc.  

computer speakers rarely have wires long enough for use in a TV setting for TV's larger then old CRTC's anyway.  
This post reminds me of a Shakespeare play.

Wow. Talk about a Rube Goldberg solution. Is RTRG an acronym by any chance?

Any $40 craigslist AV receiver would achieve the goal without risk of blowing up a presumably expensive television.