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Input Impedance of Digital I/Os in Atmega328P
The current quoted is the maximal leacage current for an input pin with pullups disabled. The input impeadence would be extreemly high when pullups are disabled and dominated by...
Monday, 22 August 2016 - 14:36
Quick on slow off for 45 Transistors
One option is to group LEDs via a 4094 latch to provide on/off control and use PWM to control the Output Enable pin for fading. This does mean several LEDs will share the same...
Sunday, 3 August 2014 - 10:00
HB100 Radar Module
FWIW, Jim, I worked with microwave movement detectors (10.525GHz) in the late seventies. One common problem was that they detect flourescent lights as movement, that may be the...
Sunday, 3 August 2014 - 09:51
Digital Ultrasonic Cleaning
Quote:I still use rosin core solder but the rosin never makes it to the board. First I put the water washable flux on the board. Then I put a blob of solder on the soldering iron...
Wednesday, 25 July 2012 - 14:24
negating motor return current in H-Bridge
Quote:as you know in H-Bridge usually use 4 clamping diodes(I don't know their exact name!) to restrain motor return current when It's working with PWM, diodes lead return-current...
Tuesday, 27 September 2011 - 17:27
How warm should a resistor get?
Hrmm, what is missing here is the Temperature Rise in Degrees 'C' per Watt, for the resistor in question. If it were in a TO220 package assume 62.5 Degrees/W (D/W) above ambient....
Tuesday, 27 September 2011 - 17:00
What do you think of this PCB design?
What are CR1 & CR2 on the USB interface? CR1 on D- is before the 22 Ohm resistor while CR2 on D+ is after the 22 Ohm resistor. C14, reset capacitor must go to GND not VCC. Can...
Friday, 29 July 2011 - 13:28
Fuses issue?
Quote:Moral: the ATmega32 microcontroller doesn't like too much the fact to have more than Vcc+0.5V on its pins and it could partially break for that!Guess what the datasheet says...
Thursday, 21 July 2011 - 13:37
How can one remove/dissolve potting compound?
Quote:It is in what appears to be expoy potting compound. we used to use a Ciba Giegy LC177N resin and HY956 hardener in proportions 10:1 by weight for potting. They had a solvent...
Thursday, 14 July 2011 - 15:47
Communication and Setup
JC wroteQuote:Wouldn't a critical factor in selecting the bus be the distance between the units? And don't forget to include the speed of the interface in your decision. Ron.
Tuesday, 5 July 2011 - 15:42
level signal
Quote:Shouldn't be necessary - I don't think the programmer will ever drive it high - just float or drive low.While it may not drive High to 5V it may have a pullup to 5V. Don't...
Sunday, 22 May 2011 - 16:30
What is the most common flashsize in a MCU application?!
Quote:How long is a piece of string?It is exactly twice as long as it is from one end to it's center. As for Flash size as a common denominator I choose AVRs by their...
Sunday, 22 May 2011 - 15:50

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