Archive for the 'Computers' Category

Pulse Voltage Boost Version 3

Tuesday, November 8th, 2011

The major issue with using Dick Cappel’s voltage boost circuit to drive a MOSFET is that a resistor would be used to pull down the gate voltage. This issue can be addressed by adding another transistor to actively pull down the voltage at the appropriate time. An additional transistor (an NPN) can be used very […]

A Better Circuit to Boost the Voltage of a Pulse

Monday, November 7th, 2011

Dick Cappel has a very nice circuit for boosting the voltage of a single pulse (or PWM signal). It costs an additional transistor compared to my previous post but it allows the boosted voltage to drop to zero (take the output from the collector and remove all of the components right of the base resistor […]

A Hack to Boost the Gate Voltage of a PWM Driven MOSFET

Wednesday, October 26th, 2011

...and why it is almost certainly not the right answer to the problem of having a logic level signal and a non-logic level FET. Mark VandeWettering posted an entry concerning the problem of driving an IRF510 MOSFET from a microcontroller running at 3 volts. The basic problem is that the threshold voltage of the IRF510 […]

“Just One Word: RepRap”

Sunday, April 25th, 2010

With apologies to The Graduate. Years ago I was very interested in 3D computer graphics. This was back in the late 80s and early 90s when Silicon Graphics reigned supreme and simply being able to rotate a Phong-shaded object on the screen in real-time was a pretty impressive achievement. Today, of course, the cheapest computer […]

PYRO A/V Link and Linux

Wednesday, October 18th, 2006

If you are having problems getting a PYRO A/V Link to work correctly with linux (dvgrab and kino), check the switch settings on the PYRO. Contrary to all of my expectations, the setting for “DV Camcorder” (switches 2 and 3 down) works perfectly for me, whereas all of the other documented settings cause the capture […]

The World at 56k Bits per Second

Sunday, May 8th, 2005

The broadband internet connection (provided by Adelphia) is currently working. This morning, however, it was not working, nor was it working last weekend. The week before that it was down more than it was up. Although we have a phone modem for use as a backup connection to the internet, using it is an exercise […]

Activation, the Tale of a Customer Lost

Wednesday, April 27th, 2005

Last weekend Nagscifi’s copy of Norton AntiVirus decided that it needed to be activated. No more downloads of antivirus definitions and patches, no more email scanning, no more file scanning, in fact, no more antivirus protection of any kind. Needless to say, Nagscifi’s laptop is now running an antivirus package produced by one of Norton’s […]