I'm in China for work right now. I have no way to upload photos, but I want to tell you about the greatest electronics store I've ever been in.
The backstory: I built a piece of equipment in Cleveland and brought it here for our production facility to use. When I assembled it and plugged it in, the Chinese electricity fried its power supplies. (Yes, I had switched them over to 220V.) Not just any power supplies: these provide current regulated to the third decimal place. I had paid $275 each and I had four business days to get it working. The solution? Drive to a store an hour away.
When we walked in, the first thing I saw was a glass counter piled high with different thick bundles of wires. From six feet away I could see about 50 recognizable types of plugs, jacks, wiring harnesses, and connectors. This was a wire connector vendor. That counter was eight feet wide. It was the first of maybe a half dozen wire connector vendors I saw.
There was a fan vendor. A counter with an impossibly organized pile of small project boxes - aluminum or plastic cases you could build circuits in. LED vendors with spools of flashing lights ready to put into a pick-and-place assembler. One person selling light housings - complex extruded and machined aluminum domes with fins to dissipate heat from a high-power LED. It went on and on. Each vendor had six or eight feet of space.
The place was jammed with people. The sellers didn't hawk, didn't reach out and try to entice us. Navigating the place required a body-and-mind dance of politely slipping through the crowd while scanning the visual onslaught for the parts we needed. It was a warren of narrow angled aisles. If I had to guess, I'd say it was about the size of a largish restaurant. It was China's Radio Shack, an order of magnitude more well-stocked than ours ever were.
We found some suitable power supplies, in three stalls along one wall. At each, we negotiated price and checked specifications. The stall where we made our purchase specialized in sensors: meters for airflow, sound level, light intensity, temperature and humidity, force, electrical current, everything. They even had several oscilloscopes. It was six feet square, and every square inch of the walls and countertop was hung or stacked with something. One of something that they had more of elsewhere. The price for my power supplies? USD$25 each. One-eleventh what I had paid.
That was the first floor. There were four.
The upper floors were progressively cleaner, more open, and less crowded, and sold things that more closely resembled finished goods. On the top floor they sold computers, but the prices were comparable to what we'd pay in the US.
Why does this place exist? Here's my theory: if you are running a factory and need to fill an order for a customer fast, you can come here for the parts. In America we'd have no alternative but to mail-order, but there is such a density of electronics manufacturers in Shenzhen that they can support retail sales of quantity parts.
I got back to the factory and instantly regretted not having bought screwdrivers, crimping tools, voltmeters, soldering irons, and a dozen other things. My Chinese coworkers had improvised a fine screwdriver by filing down the tip of an Allen wrench. Oh well.