Can you explain why it is 6 * (3/9) ,Why don't we add 5kΩ resistance too, How is this a current division,what is the formula for this.Thanks..
121242
As far as I know, current division for spesific place's formula is: Ix=(Req/Rx)*Isource   However, here,the solution is 3/(3+2+4)*6. How is this a current division ? Can you explain this to me
55201
I have trouble with finding out resistance of a resistor. It has 5 bands but somehow I cant get the code right.
50914
I have 3 12VDC/40A automotive relays () that I want to use with my Arduino. Based on the tutorial I am following () I need transistor, resistor, and diode. I am not an electrical engineer therefore I am unsure about the parts and calculations I made. For the start, relay coil resistance is 90+-10% Ohm per datasheet. So I proceed by calculating the current flow.  Voltage=Resistance*Current Current=Voltage/Resistance Current=12V/90 Ohm Current = 133mA  For the transistor I can get 2N3904 or 2N4401. At this point I have to calculate resistance for the base of transistor. In tutorial its as following  hfe = Ic / Ib Ib = Ic / hfe Ib = 0.03 A / 75 Ib = 0.0004 A =&gt; 0.4 mA R1 = U / Ib R1 = 5V / 0.0004 A R1 = 12500 Ohm  2N3904 datasheet states the H(fe) is 30-300 when lc = 100mA (mine is 130mA) and Vce = 1V. At this point I have no clue what is going on, thus I need help. Edit: Here is what I ended up with. RLY1 in the picture is 12VDC/40A ()
48045
When we have resistors in series, the current through all the resistors is same and the voltage drop (or simply voltage) at each resistor is different.  Question 1: It is fine that voltage drop (potential drop) across each resistor is different because each resistor offers different resistance (suppose). but how is the current through each resistor same? If we have resistors of different resistance, shouldn't the current be different through each resistor?  Similarly, when we have resistors in parallel, the current through each resistor is different but the voltage drop at each resistor is same.  Question 2: Current through each resistor is different because resistance of each resistor is different (suppose). but how is the voltage drop across each resistor same here? Shouldn't the voltage drop at each resistor be different because each resistor offers different resistance?
95325
I have a power supply of 5 volts @ 1A. I want to reduce the current from 1A to 250mA. Which resistor should be use?   I tried this equation(Ohm's Law):  R = V / I  = 5/(0.75)  = 6.66 Ohms.  I tried the 6.66 Ohm resistor but it only reduce few mili Amps.
13239
Can I simplify this circuit to just one resistor? How can I find the equivalent voltage of the current source in this circuit?
83528
I want to join 3 resistors connected in parallel into one. Like this   If for the total resistance I use  $$R_t = \frac{R}{3}$$  But what about the power of them?
119481
I'm doing a simple lab (I'm a hobby EE) to reinforce my ohm's law math and learn a little about how to do proper measurements with a multimeter.  I have simple circuit with a 2.2k ohm resistor connected in series with an LED. Everything works fine up to the point I go to calculate voltage drop across the resistor and LED.  My initial calculations only accounted for the 2.2k ohm resistor. As such I got the full voltage dropped across the resistor. However, when I measured the circuit for real I found the result to be nearly half of the input voltage, which would indicate to me   My math is wrong There's resistance left unaccounted for   The only thing left to account for is the LED. What is the best method for determining the resistance of a simple LED? I tried doing what I do with resistors (hold it up to the probes with my fingers) but I don't get a proper reading. Is there a technique I'm missing here?
19342
What is the difference between the Resistance and Impedance? When we will say it is an Impedance and when we will say it as an Resistance? Can you explain it with diagram (If possible) and real time example.    And how the reactances will form in the circut where the Capacitors and inductors are not available in our circuit? How we will find the reactances in the circuit and its values in real time?   I means is this possible to calculate the reactance by using any instrument? Do the reactance was intentionally kept by the designer or generally it'll forms with in the circuit?   All answers are appreciated.
79810
I know the path of least reisistance has been clarified already However, to derive the equations you need to assume that the voltage of each parallel component is equal. But we know for a short circuit current the voltage is zero (By Ohm's law!) So there is a glaring contradiction!
66458
I need to find the Equivalent Resistance across A and B. The problem is, I don't know which one's are in series and which ones are in parallel. How do I identify which ones are parallel or series?
81489
Can somebody help me solve this. I need to find the equivalent resistance of these resistors. I really don't know where the trick here is. If somebody could help me I would really appreciate it
116498
This is an in-spirit follow-up to my earlier    So I'm an electronics hobbyist, and I've been curious for a while about the proposed new component, the memristor. My research has turned up  link demonstrating the creation of one, and now I'm wondering, how do you define and measure a memristor? If a memristor relates charge and flux, how does an oxidized metal perform like this? finally, do all (or most) metal oxides have these characteristics?  I realize that this is probably a lot, but what I've seen out on the internet regarding this has left me very confused.  Thank you for your help.
82819
I am having a hard time answering one particular question about our experiment.. In our experiment, R1 and R2 were set to 1Meg each and later to 10k... I understand the need for R1 and R2 a bit. Without R1 and R2, the voltage sharing wouldn't exactly be 50-50 for both D1 and D2 because no two diodes are completely identical. D1 and D2 will both have the same leakage currents (without R1 and R2) since they are just in series. However, they probably will have non-identical IV curves, so this particular leakage current will result to V@D1 /= V@D2.  The question I am having a hard time is that, why is V@R1 + V@R2 /= 10v when R1 = R2 = 1Meg?... One the other hand, those two voltages add up (to 10v) when R1 = R2 = 10k... I included the 60 ohm source resistance in my diagram for completeness. However, as I can see, both D1 and D2 are reversed biased and thus, they offer a very large (reverse resistance) which should be much greater than the 60 ohms. Even with the parallel combination of 1Meg and D1 reverse resistance, it should still be much greater than the 60 ohms. I tried thinking of an answer in terms of the RD1reverse//R1 = Req1 and RD2reverse//R2 = Req2. Req1 + Req2 (series) should still be much more than 60ohms and I thought that the 10v should still show up at the node of D1 cathode. Yet in our experiment, V@R1 + V@R1 &lt; 10v.  Can anyone point me out if I am thinking this in a wrong way? Some tips/first step hint would really be appreciated  Edit: question answered thanks to @CL. Assuming D1 and D2 are open during reverse bias for simplicity and noting that Rmultimeter = 10Meg, V@R2 (shown on multimeter) = 10v * (1Meg//10Meg)/((1Meg//10Meg)+1Meg+60) = 4.76v measured.
120059
how are we supposed to do this question if resistance is given as 1 ohm
92626
We have the following diode circuit.We have found when the diode is on and off.Now the teacher gave an extra question.What is the ouput Vo (represented in a graph) when we have an input of  a) \$V_i = 100 sin(wt)\$  b) \$V_i = 150 sin(wt)\$  She then solved this exercise .I see the graphs but I dont understand them? Can you please explain them to me? Here is the solved exercise (Excuse the sloppy drawing)    Here are respectively graph a) and b)
112857
I learned in high school the basic rules of how to compute resistance between two points, given a network of resistors.  You try to rearrange the circuit so into parallel parts and series parts, then compute the resistance of each piece individually using those rules, until you're left with just one number, and you're done.  Maybe I explained that poorly, so consider the following schematic:         &ndash; Schematic created using   Sorry it's so large, that seems to be the default.  Anyway, it's easy to compute the resistance from A to D (regardless of the values of the all the resistors)- A-B-D, A-D, and A-C-D are all series connections (easy to compute) then you combine them with the parallel formula and you're set.  But!  How do you compute the resistance from B to C?  There seem like lots of possible ways to think about it, and they all generate different answers.  I've left the specific numbers off the diagram because this isn't homework and I don't care about the answer specifically, I just want to understand the principles involved and how to solve the problem.  Any help, or links to especially readable guides, would be very much appreciated.