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Training the hand and mind since 1982.

Thursday, February 14, 2013

NE555 Timers From China

Just orders 100 NE555 Timer off ebay for $9.98 with shipping . Got it within 10 working days via 1st class China Post. Each chip cost around $0.09 each. This chip was marked with the Texas Instrument logo NE555, HYC 252G. I have no idea if they are genuine they are probably grey market re-badged.

Our normal distributor each chip is $0.24 per 100 with shipping not included. Also a lead time of 2 months with our PO system (snail mail) and shipping (UPS ground). Overall we order about (5000) NE555 per year, so if we switch over to China we would save about $700 per year, but the catch is you need an ebay account and a credit card, slim chance of that happing.
 
I tested all of them in a astable mutivibrator circuit with a 97% pass rate, 3% failed with voltage output issues, they did oscillate at a frequency but at a diminished voltage. A 97% pass rate is fine for what we do, all of our designs we add an IC socket so if it fails it's an easy swap. Also our circuits a novelty items (buzzers, LED flashers, etc.) and laboratories, there not in high reliable systems / life support or in safety systems.

One chip I tested was really strange. It ran about 40 times higher frequency that what the other comparison chips in the circuit. I placed the chip in the circuit a half dozen time and it came back to life, really weird.

I set up a zif socket and a few resistor and caps, 2K, 1K, and a .1 uF cap and a 1uF cap as a filter cap on the supply.



 ZIF Socket Bread Board
 

 Good Signal


Bad Signal The 3%


NE555