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Search for LM741 in Topics

still on LM741

the point is i have the IC, and i have a board on which i can mount it.the question is which pin do i connect to what resistor and to what pin

Question by Abume4life    |  last reply

Help with LM741 op-amp? Answered

Just to test it out, I hooked up a voltage follower with a LM741 Op-amp. But, when I measure the voltages, it doesn't work. When I have problems with such simple circuits, it makes me want to kick a small animal. Please, save the small animals, help me with my circuit. When I measure Vout, I expected something somewhere around 7-8 volts, but I'm actually getting 13-14 volts. I also tried changing the resistors in the voltage divider, but the output did not change. I'm getting my power from an unregulated 12v 1A wall transformer, but I measured it at around 15v unloaded. I replaced the chip once to rule out static electricity as the problem, and I got an output 0.1 volt higher. Any ideas?

Question by WerdnaN    |  last reply

Comparator Inputs ?

On the two inputs of a standard comparator op amp (say for example  LM741)  they usually  connect resistors from both the positive and negative voltage rails .Why do they do this and how does this work . This has been on my mind for a really long time . Could someone give me a really detailed explanation maybe with images if possible , cause this would be really helpful in the building of my next project .Most of the tutorial videos out there , i don't understand either. Thank you in advance  

Question by Strontium    |  last reply

is the LM741CN op amp work same as the LM741 op amp? Answered

I'm making a distotion pedel and radio shack has the LM741CN but not the LM741C op amp.

Question by Flaky_Jay's    |  last reply

How Op Amps work? Answered

I was wondering if anyone could explain how an op amp like the LM741 works. I don't mean I want to know what's going on inside it, but more along the lines of "how can it be wired up?" and "what could it be used for?"

Question by tylervitale    |  last reply

Problems with logic(NAND) gates? Answered

I MADE a circuit that basically detects when an IR beam  is cut using a LM741 opamp .AS shown in the schematic i've connected the output of the opamp to the  two transistors (which is a nand gate) ,so when the beam is cut the output of the transistors should be high but instead the led at the collecter of the transistor glows only brighter. should i use a nand gate in a DIP package ?also when i individually measured the output of the opamp it showed that there was constantly 1.5 v coming out i tried measuring it with both opposite polarity leads of the multimeter  ,still  it showed a 1.5 v output,why does this  happen?PLS help.i need it fast.

Question by Strontium    |  last reply

Op amps? Which one is best?

I have a couple op amps collected over a couple years, and I am working on a design for a linear power supply, but have stability issues, and a "down to -V" common mode input voltage for op amps is a difficult parameter to find. Constraints: * Inputs must work down to as close to the negative supply rail as possible  * needs to be stable when used in a feedback loop for a linear power supply design * low noise / offset / blah blah good good goodies?? Hopefully? I'm actively testing these in a basic comparator circuit to see how far I can get the inputs to the -vee (or ground) before the op amp stops working as intended.I have tested the LM324, LM386, UA1458TC, LM741, and a few of the LT one's. Only the first 2 work well on a single supply w/ the inputs near ground or Vee LM324; // slow LM224; // ditto, but in weird thicc package LM386; // slow LM741; // ancient relics of the past, not rail to rail by any means, sucks IMO. UA1458TC // ancient relics of the past, not rail to rail by any means, sucks IMO. LM318H; // it's in a fancy metal case :D TL072CP; // JFET inputs, limited output current and the output can't go below the noninverting input. TL2072AC; // ditto. OP37; // These things aren't even that fast and can't work at unity gain. OP27; // ditto LT1007; LT1167; LT1191; LT1363; CRAZY fast, 1000V/uS!!! Maybe too fast... LT1360; LT1112;

Question by -max-    |  last reply

Simple PIR circuit, need review

Hi, I'm working on a simple circuit. The idea is to have a portable device that lights up when I stand up at night. I have a PIR sensor that triggers 3 LEDS. I use a LM741 as an OpAmp The leds are type 3528. Though these LEDs are supposed to be powered with 12v, I'll use a 9v battery. My main concern is the battery life, tha'ts why I use 100k resistors in stand-by, to limit the current. R3 is used to fine-tune the threshold on the inverting voltage. PIR outputs:    3.3v when it detects motion,    ?v otherwise (but yet >0) Could anyone give me some tips or advice on how to improve my circuit? Thanks, Antonio

Topic by stills    |  last reply

I've got a relay switching problem. Answered

I've got a relay problem.i made a proximity sensing tubelight that goes on/off when an object moves above it .i used 3 ic's :lm741,cd4017,and a 555 timer and i added a relay to the outputs of the cd4017 counter to the relay via a transistor to protect my ic's.however when i don't connect the 220v ac to the load of the relay it functions fine but when i connect 220v ac to the load ,the relay keeps clicking on and off.i have seen the voltage ratings for the relay .it is a 5v relay and can handle 250 v ac but it does not work properly.The whole circuitry is powered by a 9v battery.i am not sure whether it is a problem of not enough power or something else..i'm a electronics hobbyist and i need help .PLS ANSWER?.

Question by Strontium    |  last reply

Op-Amp Help

Hi- So, I made the circuit below to make sound-reactive blinky LEDs for a halloween costume (the round thing on the left is a condenser mic). I think I just got lucky that it worked, because I'm no genius when it comes to op-amp usage or design. Now I want to adapt it to control something else that needs a slightly higher voltage than the LEDs. Basically, I'd like the output to swing as high as V+ when the mic input is "loud" (a relative and possibly adjustable level). I've messed around with various resistor values as well as adding or removing resistors in places it seemed like it would help (according to the LM741 datasheet). All to no avail. Anyone out there who might know what to do? Again, I want the mic input to cause the output to go as hight as V+ (9V in this case) when it's loud, and be more or less at 0V when it's "quiet." Thanks in advance, _mykle

Topic by deadbilly    |  last reply

741 Signal amplifier Answered

How would I go about creating an amplifier using an LM741 to amplify a 0mv-400mv signal to a 0v-4v signal? All the circuits from google or textbooks don't work, or produce strange oscillations. The only way I can get it to work is in inverting mode, where I can get -4v-0v out, which isn't very useful. My specific application for this is for a digital thermometer. I intend to amplify the 0-400mv analogue signal from an LM35 linear temperature sensor, then somehow sample that without using loads of logic or transistors and convert it to decimal or binary, then drive a dual 7-segment display to show the temperature. I have a prototype made using 20 comparators and 10 xor gates, and countless diodes, so if anyone could advise me on an easier way to do that, that would be great. And no PICs/AVRs, I know how to use them and have programmers, but I prefer to do "real" electronics using CMOS chips.

Question by andy70707    |  last reply

linear regulator design, darlington, 5V dropout @ 2.5A !? Answered

The question says it all, really. I built up a linear power supply shown below. My unregulated 12V supply can fall as low as 14.7V @ ~ 2-3 A but if I end up being unable to go higher than 9.5V at 3A. Because I'm driving a motor as a load, the current drawn is very dirty. At 10V I see small dips that correlate to dips in the supply voltage when it goes just under 15V. So what can I do to help alleviate this, as I was under the impression that I would see a absolute maximum of 3V of dropout, not a whopping 5V. (p.s. the maximum gate current into the S8050 is 10mA, but currently set to 6.77mA w/ a 10 ohm resistor) p.p.s: MY design uses an LM324, which is really not the best, as it's slow and cannot sink much current. To alleviate the first issue I simply added current mirrors to aid the op amp in sinking current in a simalar fashion as a current source used for an open collector outputs. What op amp should I use instead for better performance? I suspect the LM324 due to it's low slew rate and low GBP may cause poor high frequency rejection (esp. if I choose to use a switching pre-reg) and poor high frequency load regulation (causes poor transient response on the output) Op amps I can choose from: LM324; // slow, from my testing, this one has inputs that work to ground :D LM224; // ditto, but in a weird package LM386; // slow, but from my testing, this one also has inputs that work to ground. LM741; // ancient relics of the past, not rail to rail by any means, sucks IMO. UA1458TC // ancient relics of the past, I don't have much knowledge of them. Inputs do not work to ground. LM318H; // its in a fancy metal case :D TL072CP; // JFET inputs, but I think the output current is limited and the output can't go below the noninverting input. TL2072AC; OP37; // These things can't even give a stable output by themselves! OP27; // ditto LT1007; // have not messed with it much LT1167;  LT1191; LT1363; CRAZY fast, 1000V/uS!!! Maybe too fast... LT1360; LT1112;

Question by -max-    |  last reply