I recently read a discussion on an electronics forum where someone had trouble getting an IR2104 to work correctly. He had bought these from a shady online store and could not get the correct signals to come out. I offered to analyze the chips, and one of the contributors to that discussion very kindly sent me a couple of them.
The IR2104 is a half-bridge MOSFET driver, which is used to drive the FETs in circuits like DC-DC converters and class-D power amplifiers. It’s made in a high-voltage CMOS process and is capable of driving the high-side FET at voltages up to 600V. The original designer and manufacturer is International Rectifier (IR), one of the first manufacturers of diodes, transistors and power management ICs. Currently the IR2104 is manufactured by Infineon, after it acquired IR in 2015.
A while back I dissected the Maxim DS18B20 temperature sensor, along with a counterfeit one. Today we’ll have a look at a couple more 18B20s from different manufacturers, all of them Chinese. I found a web store in China that sold me the XSEC SE18B20, the Novosense NS18B20, the 7Q-Tek QT18B20, the GXCAS GX18B20W and the UMW (Youtai) DS18B20. Prices varied from 65 cents to about two Euros apiece.
To get an idea of their performance, I put one of each on my Arduino board and placed it outside, where it was quite cold:
The 486DX series were the complete, full-performance versions of the 486 processor line. Unlike the low-cost 486SX, the DX versions contain an FPU, which significantly speeds up floating-point calculations compared to the earlier 386. In 1992 Intel delivered another huge leap in performance by simply doubling the clock frequency of the 486 core from 33 to 66 MHz. Motherboards at the time could not cope with such high speeds, so the bus clock remained at 33 MHz. Although 40 and 50 MHz speeds were also available, the 66 Mhz version was by far the most common and remained the processor of choice for most high-performance 486 computers until Pentium systems became mainstream around 1995.