Basics

4X4 matrix keypad-74c922- source code
hi...... im trying to interface a 4x4 matrix keypad using a 74c922 decoder to an Atmel micrcontroller ...in c- programm....... i would appreciate some pointers in how to create d source code that will read from the output of the decoder...according to key pressed... thxs bb ... 29 Mar 2006 02:42

Varistor rating
Hi all, I've two varistor....from two different PCI dialup modem. TUR 07271 and ZOV 07D241K is written over it...was is the voltage and current rating likely to be, how to read it?? Thanks ... 23 Dec 2005 02:31

IR2153
http://www.irf.com/product-info/datasheets/data/ir2153.pdf I tried to use the IR2153 to run a half bridge using two n-channel mosfets as in the circuit diagram on the first page of the data sheet, and it didn't work. I discovered that HO only sinks, it does not source. LO works; it sources and sinks, and the cap f... 15 Nov 2005 21:02

phase lock loop (PLL)
hi i choosed the VCO resistor & capacitor According to the formula ( f min= 1/(R2(C1+32pf)), f max =(1/(R1(C1+32pf)))+f min) my Fmin is 10KHZ and Fmax is 20KHZ. And i have not connected any loop filter. i have checked the offset frequency. But the output is very worst, I'm not getting the exact squrwave(... 12 Jul 2005 10:46

PIC based Pt100 RTD temp sensor circuit
Can anybody give me any hints ideas or circuits to allow me to read the temperature from a Pt100 RTD probe in to a PIC microcontroller? Regards, Mark ... 8 Jul 2005 14:45

Impedance
How does impedance mismatches alter signals? I know you lose HF but always wanted to know how different frequencies are affected by different circuitry. Thanks ... 17 May 2005 10:41

Home wiring
Hi Group, I am wiring a room in my basement. It is a new room. I have purchased 2 books on home wiring and I am confident about doing the work myself. I have 4 plug outlets, one light switch, two light ceiling outlets. I am 'daisy chaining' these together to go on the same circuit. As such, I am pig tailing the ... 14 May 2005 08:48

H1102 transformer functions
Hi, I saw the datasheet of pulse H1102 ethernet magnetic but cannot understand the theory. I want to know what is the function of the transformers interfacing to the RJ45 ethernet network. Is it used to reject common mode noise? Besides, why do I need to use the magnetic to interface to ethernet? Thanks! ... 24 Apr 2005 05:33

center tapped transformer
I made this dice pyramid that I want to light from inside with incandescent bulbs and I bought this radio shack 12.6 volt xformer, but it has a "center tapped secondary" and I don't know what that means or how to wire it to power some 12 volt bulbs. can anybody help? -- billb ... 14 Feb 2005 20:58

LM3915 as LED fuel gauge?
I want toadd a set of gauges to my fuel management system. It will require one for each tank and 3 standard gauges take up to much room and cost a bunch so I am going to DIY it. Follow me through on this: The sender is a variable resistor with a range of 240 Ohms empty to 33 Ohms full. If I put a 240 ohm resis... 14 Feb 2005 20:54