This tag is nearly useless. Consider using more specific tags to narrow your question down.

learn more… | top users | synonyms

-5
votes
0answers
17 views

Request a lead acid battery charger for 12v 200AH battery

i request from you a circuit that i can use to charge two lead acid batteries each 12v 200AH caracteristics : auto cut off using relay no integrated regulators LMXXX or comparators zener diodes ...
2
votes
2answers
75 views

Is there a simple circuit that outputs (min+max)/2 of a single-ended signal given as input?

I have a digital, single-ended, signal that randomly varies between +400mV (logical ‘1’) and 0V (logical ‘0’). I am looking for a circuit to calculate the DC value that corresponds to the average ...
2
votes
0answers
31 views

Make a simple sim card reader circuit

I'm trying to implement a sim-card reader for my own. I followed step by step the guide on www.ladyada.net site but it does not work as it would be. My PC and softwares i used to read/write data ...
2
votes
2answers
60 views

2 LED Parallel circuit help?

I need to make a circuit with 2 leds, 1 green 1 red. If the current flows, green led will light up, if there is a break in the circuit (open circuit) it will light up another led as red. I don't ...
0
votes
2answers
40 views

How to make 2 bit or more half adder circuit

I have no idea about electronics, this semester school gave us a strange and confusing lecture about circuits which we shouldn't take because we are no engineer or something close. Question is we ...
1
vote
2answers
55 views

Question about this RC circuit and voltage across the capacitor

I just have a small question about the below problem. How did they get Vc of the capacitor to be 12 V before the switch is opened? Doesn't the resistor use up some of the voltage?
-2
votes
2answers
52 views

TIP31c Audio Signal Issue [on hold]

I've wired a simple LED to respond to a music audio signal as per the schematic, however my LED stays lit as soon as I connect to something, music playing or not. Anything I'm doing wrong? LED: 2.8V ...
-1
votes
0answers
35 views

Are plane's black boxes essentially useless tool in the modern age and how to improve upon it? [migrated]

I am just reading the latest news on the air plane crash that happened couple days ago and it dawned on me that one too many times have I read a story where after black box is obtained, it provided no ...
0
votes
1answer
49 views

Trouble finding the input in this circuit diagram

Currently having trouble finding the input in my circuit diagram. I am assuming "z" is my output. As of now my input equations I have figured to be: Da = BC Db = CB' + BC' = C(+)B Dc = C'A' Z = ...
0
votes
1answer
29 views

Circuit for amplification and protection against input inductive spikes

I'm working on a permeability measurement project and my setup includes a primary as well as a secondary side of a coil. I need to measure the flux through the coil, hence on my secondary side I have ...
1
vote
3answers
45 views

Dependence of output voltages of an op-amp on rail voltages

I want to use an op-amp as an inverting amplifier to convert negative voltages to positive voltages, simulate this circuit – Schematic created using CircuitLab If my input varies from 0 ...
0
votes
1answer
23 views

Write V_final in terms of V1

simulate this circuit – Schematic created using CircuitLab Being \$V_1=10\sin(100t)\$ and \$V_D=0.7\$V, it is asked to find the output potential as a function of \$V_1\$. I made: ...
1
vote
1answer
44 views

Magnetic contact circuit

Which is the best circuit for using a magnetic contact for turning on a LED strip? I would like to turn on a strip led with 12V 7A battery, but: 1 - if I use only the magnetic contact it will be ...
0
votes
0answers
45 views

Fast peak detector circuit with xor

I'm interested in identifying the peak of short 300ns pulses. Ideally I would have a circuit like the one detailed here: Peak Detector 3 (the second one) cc: em-fields That would provide me with a ...
0
votes
2answers
54 views

1/6 Clock Frequency Divider

How would I design a circuit made of rising edge triggered flip flops and inverters to make its output 1/6 of the clock frequency. Cheers
1
vote
2answers
229 views

How do I work out what resistor to use?

I am trying to work out what resistor to use in a circuit. The circuit is a series circuit. The power to the circuit is 5.5V, with a switch, which connects to a GPIO pin on the RasberryPi. I believe ...
1
vote
1answer
103 views

Problem in Basic 555 Timer Circuit

I am trying to build a simple LED flasher circuit using 555 timer IC. Tried building it on breadboard and simulators several times but that is not working. As I am a beginner I think I am making some ...
0
votes
0answers
37 views

When to use Delta-Wye Transformation?

I have these two circuits needed to be simplified. Now in Case 1, is R4 and R5 in parallel connection? In that case, how does the equivalent circuit look like when R4 and R5 is simplified? Or if ...
0
votes
0answers
9 views

need to change the runlength units in modelsim software

how to change the run length in modelsim software..i.e nanosecond to picosecond.In the modelsim software didn't able to change the run length units can anyone explain it..
0
votes
1answer
32 views

9X8 led array question

I'm completely new to electronics but want to build a blue light led array 8x9 with a 12V input and have no idea how to do this on a protoboard! If someone could help with a schematic it would be ...
-3
votes
2answers
89 views

How electronic circuit works? [closed]

if current flows through phase and fed to the desired circuit and electrons after travelling through circuit and comes out through neutral and then to ground. then what make circuit work if electrons ...
2
votes
2answers
46 views

What are some examples of MSI (Medium-Scale Integration) circuits that are used for doing arithmetic?

Just looking for some examples of MSI circuits used for doing arithmetic. I understand MSI circuits have more than 10 but less than 100 gates, or less than 500 components.
0
votes
3answers
91 views

How can this circuit read a value for amps at 0 volts

I made a simple circuit using this: It can tell you the voltage and current along a wire if you mouse over it. The wire down the bottom reads 4.55mA and 0V (the little yellow dots actually move to ...
0
votes
2answers
74 views

Calculate pull-up resistor for phototransistors

I have made a sensor which uses six IR phototransistors, three per sensor block, opposite it is a matched IR diode(940nm). This is in turn connected to a MCU. The function of the circuit is an ...
0
votes
3answers
40 views

How could I set up a circuit that keeps track of strikes in a baseball game using D flip flops in Multisim?

What I want is two LED lights and a push button. When the push button is pressed the first time, the first light lights up. When it's pressed a second time, the second light lights up. When it's ...
0
votes
1answer
56 views

how can we detect overspeeding through sensor or by building up circuit ??

I am working on project to detect overspeeding through sensor. but i am not getting any information regarding sensor. All i want to do, sensor inside vehicle with arduino and gsm which will send out ...
0
votes
2answers
34 views

verilog coding in modelsim

can anyone tell me the verilog coding and simulation for this design using modelsim software..i had tried a lot by the following coding but i can't get the correct result..please i need it for my ...
0
votes
1answer
61 views

Parallel circuit and Ohms law

Theoretical questions with ideal components.(R2 is 10 Ohm) 1) parallel circuit. R1 and ammeter, If I have a parallel circuit of 2 resistances, both zero Ohm, the current would split to 2 and each ...
0
votes
0answers
20 views

Common drain CMOS single stage amplifier with current bias with positive and negative rail analysis

I was presented with a classical problem where i am asked to evaluate the output of this circuit when VIN = 0 and then 5 volts. The NMOS will be off as long as Vgs is less than Vtn. The NMOS will ...
0
votes
1answer
60 views

Identifying a component on the circuit board of a mobile phone

I need to identify this component which I found on a circuit board inside a mobile phone.
0
votes
2answers
74 views

Bench power supply “Issues that rouse during build”

I'm building a power supply, based on this instructable and this one I am using 24volts DC power supply, 7+ amps circuit is based on LM338 / 7805 / 7812 Circuit is working although few things ...
3
votes
1answer
98 views

Using a MOSFET to switch a High Voltage on a Capacitive Load

I am trying to bias the filament of an electron gun to -575 V, but I need to switch it on and off using a TTL signal. I have an idea for how to do it, but I would like to know if it will work before I ...
1
vote
2answers
61 views

What circuit can use a falling edge to trigger this damped oscillating impulse waveform?

What circuit can generate the waveform shown below upon receiving a falling edge trigger? The closest I've gotten is that it looks like an RLC that got charged then the loop got closed. I'm guessing ...
1
vote
2answers
74 views

Are my zener concepts wrong?

If a battery of 60v with internal resistnace 4kohm (in series) is connected to a zener diode of v_z=10v in parallel and a load resistance of 2kohm in parallel too, what will be the currents in ...
-2
votes
2answers
137 views

Boolean function and logic circuits

I have at my disposal: 2 input AND & OR logic gates and 1 input NOT logic gates. I need to prove (or disprove) that: 1) Every Boolean function in 3 variables (all 256 of them) can be represented ...
1
vote
0answers
76 views

Wired Or of Triacs don't seem to work

I am trying to make a full sine wave from two half waves wire-ORng through triacs However, as long as the triac output terminals (MT1 for both) are not shorted, the signals seem fine. When I short ...
0
votes
1answer
57 views

alternate astable multi vibrator design

Is there any alternate way to design Astable Multi Vibrator with use of only Resistor & capacitor ? ( avoid 555 Timer ) , avoid BJT if possible. my aim to make most compact Astable MV.
1
vote
0answers
49 views

I'm trying to determine the Thevenin voltage of a circuit using the node voltage method

I'm trying to determine the Thevenin voltage between the terminals a and b on this circuit: Notice that I've named the three essential nodes \$v_1\$, \$v_2\$ and \$v_3\$. I've highlighted the ...
1
vote
1answer
60 views

What is the circuit size and/or circuit depth complexity of an op-amp?

What is the circuit size complexity and / or circuit depth complexity of an op-amp? This is for comparative purposes, so I'm really after a ballpark figure and any op-amp is fine (although the ...
1
vote
2answers
51 views

How to do Norton equivalent circuit? Why part of the circuit can be ignored?

I read the solution. It said that the 10mA and 10Kohm is not going to affect the circuit, so that it can be ignored. However, I don't understand why. Please help. If I really want to include those ...
0
votes
1answer
48 views

Would this minimal NPN-based metal-detector circuit work?

I found various circuits online (1, 2), but they seem rather complicated. Would this work..?
3
votes
2answers
1k views

Can an electric circuit do recursion?

Can an electric circuit do recursion? By recursion I mean any kind of recursion, tail, binary, nested, etc: http://www.sparknotes.com/cs/recursion/whatisrecursion/section2.rhtml By electric circuit ...
2
votes
1answer
59 views

Calculating the gain and phase shift of a phase shifting circuit

I want to calculate the gain and the phase shift of the phase shifting circuit below. My approach is to derive equations to different meshes using Kirchoff's law, and then calculate the ratio between ...
0
votes
1answer
47 views

Operation Of LC circuit

I generally can't understand the operation of an LC circuit that is I cannot visualize it. I have a few doubts regarding that, please explain me? Operation: Animated diagram showing the operation ...
0
votes
1answer
32 views

supply two board with one battery

I have build a little circuit that play an audio file each time a switch is released. I used a voice board based on an ISD1820 and an amplifier based on LM386. Everything works fine with a couple ...
0
votes
1answer
32 views

H Bridge Voltage Drop w/ Motor Installed

first post after searching the net/ site for quite some time. I have this H-Bridge circuit http://www.circuitstoday.com/h-bridge-motor-driver-circuit I'm using 3 AA batteries to test this BEFORE ...
0
votes
0answers
174 views

Circuit Q - Calculating the minimum internal resistance for max 2% voltage error

I am stuck with this question. Not very confident with my approach. In the circuit below: Question reads: "Assuming you have a real voltmeter with non-infinite internal resistance and that you ...
-3
votes
0answers
26 views

Forming Larger Decoders / Encoders

I was asked if we could implement a 4x16 decoder with different sets of smaller circuits. two 3 x 8 decoders with one 1 x 2 decoder, five 2 x 4 decoders four 2x 4 decoders and three 1 x 2 decoders ...
1
vote
4answers
94 views

Thevenin voltage for a simple circuit

Trying to find the Thevenin equivalent voltage for the circuit on the picture below. This voltage is supposed to be found at the round dots to the very right in the circuit. According to the answer ...
0
votes
1answer
27 views

flow power around button laser module circuit

I have a red laser pen module: http://space-linker.com/Uploadfiles/UploadFile/2010178127739.jpg I want to be able to have it always on. How can I short the button, without having to glue or tape it ...