John asked the man what his name was. 

John asked the man how old he was.

John asked the man what his job was.


Inversion as shown (... how old he was) is necessary.                        
The tense changes because the original sentence in the direct speech is past as in "said John to the man." In some cases such as names, "is" may seem correct for it is still current or doesn't change. However, since we're referring back to the time the question was asked, it has to be "was".


How to change questions to indirect speech if we are asking about personal information?
Answers to other questions here (e.g. 1) show capacitors used to drop AC voltages to levels suitable for a LED. I've seen much simpler circuits such as the one below







simulate this circuit &ndash; Schematic created using CircuitLab

Assuming it's in a suitable enclosure, are there significant drawbacks or dangers to this circuit compared to others?
