App note: P-channel power MOSFETs and applications

Another app note from IXYS on P-Channel power MOSFET application. Link here (PDF) IXYS P-Channel Power MOSFETs retain all the features of comparable N-Channel Power MOSFETs such as very fast switching, voltage control, ease of paralleling and excellent temperature stability. These are designed for applications that require the convenience of reverse polarity operation. They have […]

App note: Parallel operation of IGBT discrete devices

Guidelines for parallel operation of IGBT devices discuss in this app note from IXYS. Link here (PDF) As applications for IGBT components have continued to expand rapidly, semiconductor manufacturers have responded by providing IGBTs in both discrete and modular packages to meet the needs of their customers. Discrete IGBTs span the voltage range of 250V […]

DIY home made portable oscilloscope

An ATmega328 based portable home made oscilloscope with ADC from Creative Engineering: It is basically a small scaled digital oscilloscope. It is capable of displaying all type of waveform like sine, triangular, square, etc. It’s bandwidth is above 1 MHz and input impedance is about 600K. The device is mainly using the ATmega328 micro-controller as […]

Extracting ROM constants from the 8087 math coprocessor’s die

Ken posted an article taking a closer look at Intel 8087 chip: Intel introduced the 8087 chip in 1980 to improve floating-point performance on the 8086 and 8088 processors, and it was used with the original IBM PC. Since early microprocessors operated only on integers, arithmetic with floating-point numbers was slow and transcendental operations such […]

Tandy 1000 upgrades / PS2-Tandy keyboard adapter

Vintage computer Tandy 1000 upgrade @ A Tandy 1000 was the second computer that I owned, the first was a Tandy CoCo. Note that I keep a slightly different mental “computers that I owned” list and “computers that I used list”. There are a few computer I was able to gain access to and […]

App note: Probing oscillator output

This application note from SiTime gives practical guidelines for the effective probing of oscillator output, shows common mistakes and explains how to identify and avoid potential probing issues. Link here (PDF) Electrical engineers often use oscilloscopes for purposes ranging from checking simple, lowspeed digital signals to accurate waveform and jitter measurements. They need to use […]

App note: Definitions of VCXO specifications

App note from SiTime about Voltage controled crystal oscillator (VCXO) specification, Link here (PDF) VCXO are frequency control devices that allow change of output frequency as their input voltage varies. In selecting a VCXO for any application, a number of device performance specifications must be considered. This application note attempts to clarify the key VCXOspecific […]

Tiny transformer inside: Decapping an isolated power transfer chip

Ken Shirriff writes: I saw an ad for a tiny chip1 that provides 5 volts2 of isolated power: You feed 5 volts in one side, and get 5 volts out the other side. What makes this remarkable is that the two sides can have up to 5000 volts between them. This chip contains a DC-DC […]

App note: Integrated supercapacitor charger

Application circuit of supercapacitor ENYCAP(TM) power management from Vishay. Link here (PDF) The MAL219699001E3 demonstration circuit is a fully transparent power management solution with a regulated 2 W output and integrated power backup. It provides a DC/DC regulator with a wide power input range from 4.0 V to 20 V and adjustable regulated output between […]

Cloning a 6502 Apple-1 in just 930 logic gates

Turning 930 logic gates into a working 6502 Apple-1 clone: Two years ago, the Gigatron arrived on the retrocomputing scene. It needs just 930 logic gates (packed into 33 standard 7400-series ICs) to create a computer that beat ‘complex’ 1980s home computers like the VIC-20 in terms of both CPU power and graphics. Without microprocessor, […]