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jrcfg's Achievements


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  1. I have read many times in various forums that allowing an input to float is a bad idea...that unused inputs should be pulled up or down. I always do just that as a result. Just so I know.... why, specifically, is it a bad idea to float a CMOS input?? And feel free to get technical.... ;D
  2. jrcfg

    ADC output

    WOW! I did not realize a couple of volts would make that much of a difference in resolution. With that 1V ref, the resolution is 0.98mV! Thankyou very much for the reply and the advice. ;D How would I go about offsetting the input to zero??
  3. Hey all you electronics guru's, I have a qestion about analog to digital converters....I think I have the concept right but would like someone with more experience to let me know...I have an anolog input that varies from ~2.173V to 2.803V (an accelerometer). I have a 10 bit ADC. My voltage references are Vdd @ 5V and Vss @ 0V. Here's the part I would like some clarification on: My 10 bit ADC and 5V reference range gives me a resolution of 5/1024 = 4.88mV/Bit. So for every 4.88mV change in my analog input, I should get 1 Bit out, correct? If I got a 10 Bit number of 0111000101 out this would be 2.211V? (4.88mV * 453 ?) Thanks.
  4. Alun: Glow plugs are simply "heaters"...they are used in diesel engines to provide the initial heat source (in each cylinder) to start combustion. Once the diesel engine is running, the glow plugs turn off as the heat of compression is enough to sustain combustion. (Diesels are relatively high compression engines).
  5. Hi all...if a transistor is biased with a +5V, 0.2mA and is switching a +14V source to a load drawing 20mA, then my Hfe is 100. Correct? What happens if the load draws more current...say 40 mA...does the bias current stay the same and only the ratio (Hfe) change to 200? I guess what I'm asking is does changing the load current (or voltage)effect the bias? Thanks. John
  6. Does anyone have any suggestions on a "good" way to cut PCB's...I have tried jig saws, tin snips, dremel tool with cutting wheel...none give a good, clean, straight cut...would a router bit in the dremel work? Thanks.
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