Duplicate

i using tps61021 boost converter ic increase input voltage 1.2v 3.3v. have designed boost converter application called ti webench. input voltage: 1.2v output voltage: 3.3v min current: 300ma the pcb have designed, measuring 3.3v, efficiency pathetic. below 25%. in bom, ti webench software recommends using 10uf 10v capacitor, using 10uf 6.3v. not able understand why efficiency low? datasheet inductor . below in tabular format have written current values have measured multimeter. fig.1 measurement of current @ different load resistance. fig.2 ti webench application output fig.3 schematic design of boost converter pin = 1.2v × 570ma = 684 mw pout = 3.3v × 105 ma = 346.5 mw efficiency = pout/pin = 346.5/684 = 50.7% how on earth did come 18.42%? similarly, 64% , 70% other 2 loads. these numbers sound pretty me @ these voltages. did webench give efficiency estimates specific configuration?

i know in magnitude spectrum of single square dc pulse (0-8v) lobes 0 @ frequencies $$\frac{1}{t},\frac{2}{t},\frac{3}{t},...etc. $$ t=pulse duration. if square pulse goes -2v 6v, formula 0 points of spectrum still same, ie. $$\frac{n}{t}$$ n=1,2,3... etc. , t=pulse duration? what difference? applying offset signal change spectrum @ dc (frequency of 0hz). if single square pulse goes 0v 8v, value of dc \$\mathcal{f}\{ f(t)\}|_{\omega=0}=0\$. if square wave goes -2v 6v, \$\mathcal{f}\{f(t)\}|_{\omega=0}=-2\cdot\delta(0)\$.

hi can make tone control circuit on arduino using lm386 , if not other ic used please me out? tone control circuit in audio system variable filter. it's used boost frequencies, attenuate other frequencies , let others is. purposes of such filtering: creative sound modifying (=adjustments subjectively result) compensating uneven frequency response of equipment , room, based on mesurements today high quality complex filtering possible in digital domain. signals ad-converted , filtering made calculations. arduino unfortunately slow , has low resolution ad conversion serious real time digital audio signal processing. if search "dsp arduino", audio examples @ best music or other sounds played through old-fashioned analog long distance phone line. thus arduino digital audio signal processor isn't serious option - except if have signal stored digital data , allow @ 10...100 times longer processing time duration of signal. in case use pc , excel or matla...

i have old audio amplifier (jvc a-gx2b) produces crackling noises on 1 of outputs. so, opened , discovered 2 largest capacitors seem leaking : can replace capacitor same characteristics (4700uf 50v), or should instead take specific capacitors audio? if yes, ones ? in addition, have interest replace capacitors of amp (not 2 largest)? 1: wear safety gloves when handling toxic leaky capacitors, remove , clean safely isoprop. , mark note polarity (-) 2 : measure dia , lead pitch dxl [mm] sort parts this 3: audio or better low esr, highest ripple current caps. < 50mohm, > 3aripple 4: better caps run cooler lower esr , rated higher temp. may not fit. 5: japanese caps have better reliability i suggest 1st choice panasonic @ digikey .. cost of shipping may more cost of caps. as suggested: cap voltage must same or more - capacitance tolerance doesn't matter, , may larger value. - large e-caps may replaced @ same time.

hello have cheap ftdi going recreate on pcb can flash atmega2560 chip onboard, ftdi has dtr line pulled low when sequence starts stays low instead of going low high after 1ms 50ms, need find out how create simple circuit when pulled low goes high, how can this, have simple components hand. my stocked parts: 103 ceramic caps 25uf aluminium caps 220uf aluminium caps some blue ceramic caps labeled "10" practically common resistors values 5v zener diodes 5v switching diodes npn transistors n channel mosfets 5v reflecting diodes can make using ? else can what's needed. many thank edwin sorry it's atmel atmega 2560 chip on pcb have serial lines , reset,5v,ground , 2 gpios on pin out. can flash ftdi. , ftdi dtr line stay low , need pluse rest line need figure out how use low signal pull reset low high right after. if try on arduino mega or uno holding down reset not work it's pulse going low high load boot manager. hence dfti dtr...

is ib current correct went kvl through first transistor your forgetting re. you need use effective resistances r4 , r6, value \$r4_e = r4 * (1+\beta) = 40,000 * 101 = 4,040,000\omega\$ \$r6_e = r6 * (1+\beta) = 1,000 * 101 = 101,000\omega\$ using base circuit looks this. simulate circuit – schematic created using circuitlab you solve using various methods, shortcut realise that, ideal vbe, voltage @ top of both emitter resistors identical. such can treat both legs being in parallel. circuit can further simplified to.. simulate circuit now should able calculate current through circuit as.. \$i_{rb} = (2.6 - 0.6)/(2,260 + 98,540) = 19.84ua\$ that makes base voltages both.. \$v_b = 2.6 - 19.84ua * 2.26k\omega = 2.555v\$ so \$ib1 = (2.555-0.6)/4.04m\omega = 0.484ua\$.. , \$ib2 = (2.555-0.6)/101k\omega = 19.356ua\$ however: these numbers make sense if transistor not saturated. question states \$i_e \approx \beta * i_b\$ indicates ...