I am putting together a basic electronic hobby kit for my friend's son who is 10 years old. I am including 2 555 timer chips, 10 each of about 10 different values of resistors. 3 each of 2N3904, BC547, BC557 transistors, 5 each of several values of common capacitors, a 5K and 10K pot. 5 green, 5 red, and 5 yellow LEDs, 1 1602 LCD display a bread board and a bag of jumpers. Also including one of my old Multimeters. I'm putting several electronic eBooks on a flash drive for him. I think this should get him started. What am I leaving out?[/QUOTE

I would add Electronics Catalogs, soldering tools, and junk electronics.

 

9V Battery connector,some switches and diodes.

Most of the 9V transistor radio batteries have low energy density and aren't cheap.

One of the Philips EE kits was arranged for a pair of 4.5V pocket flashlight batteries - can't remember the number, and I'm pretty sure they're unobtainable now. They were sort of flat profile and the terminals were two brass tongues one shorter than the other. The standard hobbyist connector for those, was solder a paper clip to the battery lead and slip that onto the brass tongue.

For the heavy duty experimenter, a couple of standard bell batteries were more convenient - and more expensive.

These days a 6 cell holder is more convenient, AA is usually enough but you can get them for C or D cells - also convenient for rechargeable cells.

 

I am putting together a basic electronic hobby kit for my friend's son who is 10 years old. [snip] What am I leaving out?

Kudos to you for trying to get your friend's son interested in electronics but, unless he has already shown a lot of interest, don't expect much. I bought one of the Radio Shack experimenter kits for my Son and after the initial excitement wore off it just collected dust.

You should add some 9V NiMH or other low current rechargeable batteries so it will be relatively safe for him to work unsupervised and a battery charger.

 

Kudos to you for trying to get your friend's son interested in electronics but, unless he has already shown a lot of interest, don't expect much. I bought one of the Radio Shack experimenter kits for my Son and after the initial excitement wore off it just collected dust.

You should add some 9V NiMH or other low current rechargeable batteries so it will be relatively safe for him to work unsupervised and a battery charger.

Maybe like as others have suggested, start off with batteries, bulbs, buzzers, toy electric motors - maybe even something approximating to a simple Morse key.

That should show whether any aptitude develops.

Bulbs, buzzers and motors draw more current than "electronics" - so aim to accommodate 2x AA cells.