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2
votes
3answers
102 views
Help with designing a circuit with logic gates
I want to build a circuit with the following design:
3 inputs
1 NOT gate
2 AND gates
1 OR gate
This is my truth table:
...
5
votes
2answers
122 views
How to analyze this diode circuit?
I am trying to analyze this simple diode circuit by hand, but I can't seem to get too far.
simulate this circuit – Schematic created using CircuitLab
Using circuit lab, it is evident ...
0
votes
1answer
42 views
Questions about RD snubber circuits
I am not too familiar with designing snubber circuits.
Can somebody sanity check the following sizing calculation for a snubber circuit?
Also: Is the undampened rise rime of the voltage due to the ...
2
votes
2answers
84 views
XML schema for electric circuits
Is there any XML schema to describe electric/electronic circuits? I am thinking of something like a netlist, but using XML markup.
-4
votes
0answers
40 views
How can you hook up a Motorola power circuit to another motherboard? [closed]
I have a Motorola razr v, power circuits. I wanted to know, how can you hook up a Motorola power circuit to another motherboard. So it can power and charge the motherboard. How can this be done?
1
vote
2answers
69 views
Mosfet Circuits Voltage
So let's take a simple cmos circuit like this:
So I get that for DC analysis \$V_G = 12 \frac{R_2}{R_1+R_2} \$ and then \$ V_{GS} \$ makes sense to me...because there is a constant \$ V_G \$ value ...
1
vote
3answers
48 views
Economical thermocouple amplifier circuit
I'm looking for the most economical circuit that reasonably accurate circuit for amplifying the voltage produced by a thermocouple (so it can be read by an ADC). For the sake of argument, component ...
1
vote
2answers
62 views
Simple RC circuit with diode question
I was trying to understand this circuit under DC conditions , but can someone explain to me why the voltage across the capacitor is 8.1v i cant seem to understand .This voltage however does go down ...
-1
votes
1answer
65 views
How involved is tapping power from a device to add LED's?
I am thinking about doing a little hobby project (if it proves to be not so difficult) and I am not exactly sure where to start. Macintosh computers have an illuminated Apple logo, and there is a ...
3
votes
3answers
95 views
Diodes in parallel
I need to protect about 5A @ 6V from something stupid like my revering the battery wires when connecting them to the circuit. I thought that I could use 5x 1A diodes in parallel, but it seems that I ...
1
vote
2answers
122 views
Problems when sharing a battery between motors and radio in an RC car
Background
I am building an RC Car that I am trying to modify to control from an Android phone.
When I connect the remote control module as well as the car circuitry (servo & motor) to separate ...
-3
votes
1answer
48 views
Calculating the voltage across the capacitor and the energy lost in an RC circuit [closed]
A circuit is shown in the figure above with \$R = 22 \Omega \$ and \$C = 10 \mu F.\$
The switch \$S_{1}\$ is closed at \$t = 0\$. The initial voltage across the capacitor is \$V_{co}.\$
What is the ...
0
votes
4answers
108 views
How input current affects circuit? Is it ignored?
All the examples I have seen so far, take the input voltage as-is and start calculating circuit current depending on on-board resistors using ohm's law etc.
Can you just ignore the original current ...
-9
votes
0answers
36 views
Need circuit diagram for train station alert? [closed]
I would like to design a bus stop Alert use transmitter and Receiver?
So i need this project circuit?
2
votes
1answer
83 views
Calculation of cutoff frequency in larger circuit
I'm having some difficulties choosing appropriate resistors and capacitors to get specific cutoff frequencies. I guess it's because I'm just considering the single pole components rather then the ...
1
vote
0answers
72 views
How to properly turn off a Raspberry Pi when instant plug-out is a criteria [duplicate]
I want to create a stand-alone internet radio device. Therefore I want to use an existing subwoofer box with connected speakers. Inside the subwoofer box there is the electronics for the sound system. ...
1
vote
4answers
119 views
Why we need clock pulse in sequential circuits?
I need to know why do we need clock pulse in sequential circuits but not in combinational circuits?
-3
votes
2answers
91 views
where to begin learning PC board designing [closed]
can someone please guide the correct path to learn board designing for computers. being specific i am just keen to design a SBC(single board computer) just for hobby purposes my current knowledge is ...
4
votes
1answer
91 views
Is it possible to control and reverse the direction of a dc motor through a headphone socket?
Yesterday, I found that it was possible to control a servo using a headphone socket with a fairly simple circuit.
I've got a project where I need to to control a dc motor via a headphone socket. Is ...
3
votes
1answer
153 views
Single power supply replacement for LM741 op amp?
I'm trying to build a twin-T oscillator for synthesising drum sounds. The LM741 heats up pretty quickly and the circuit hardly oscillates even when the feedback is at 100 per cent. Even with an LM386 ...
2
votes
1answer
103 views
Q-Point of a circuit
In a BJT or MOSFET circuit we have this curve:
What is that q-point? From my research I have the following information:
The operating point of a device, also known as bias point or quiescent ...
4
votes
1answer
69 views
Is it possible to make a multi-display adapter as an independent project?
I've been looking at the Matrox DualHead2Go, which is essentially the best/easiest way to go about using dual monitors for a MacBook Pro. Some people suggest using a USB to VGA or HDMI - but obviously ...
0
votes
1answer
50 views
24-bit parallel TFT module on circuit designed for 16-bit parallel
I've designed a circuit that connects a 16-bit parallel LCD TFT module to the SPI-connector on a RPi, but bigger TFT modules often have 24-bit parallel. Can I use a 24-bit parallel TFT with my circuit ...
1
vote
2answers
97 views
What makes these simple circuit diagrams different?
I'm kind of confused with the behavior changes of these 3 differences of a flip flop.
I made an image to easily show what I'm asking about. I circled the differences in red.. Heres the image:
For ...
2
votes
1answer
77 views
Why does my D Flip Flop Circuit have an X output?
I'm working on one of my projects and I'm having trouble with my flip flops. The project is to design the circuit for a gas pump that has a handle and a sensor. When the handle is down, the pump ...
1
vote
2answers
134 views
How to measure capacitance without LC meter?
I would like to use capacitors salvaged from old electronics, but I currently don't have a LC meter.
What would be some really simple circuits, that would convert capacitance to something I can ...
0
votes
3answers
81 views
Serial and parallel circuits and power
If I have 12V of power, and wanted to power LEDs with a forward voltage of 2V, could I only power 6 of them? Would I connect the cathode of one to the anode of the next, creating a kind of serial ...
-9
votes
0answers
62 views
1
vote
2answers
114 views
How to justify that op-amp 1 has negative feedback?
Op-amp 1 is topmost in the schematic below. I used the ideal amplifier method (using A until the end and then lim A->infinity) and also the virtual short method.
But I don't know if that's enough to ...
4
votes
2answers
191 views
Simple vending machine circuit
As a homework assignment, I was given to design a simple vending machine circuit as follows
Receives 5 cent, and 10 cent one at at time.
20 cent per snack, gives change when necessary (IE, 25 cents, ...
0
votes
2answers
130 views
Given a gated SR latch, How do I make it a set dominant gated SR latch?
Another weirdly worded question in my digital logic book. It doesn't specifically define set-dominant or reset-dominant - nor does it show how to use these in practice with drawing circuit diagrams. ...
-7
votes
2answers
85 views
-1
votes
2answers
79 views
Combine two circuit L293D
Does anyone know whether two circuit L293D can built above themselves that it allows flow high current?
1
vote
2answers
71 views
Circuit analysis with nodal analysis
[EDIT] I'm going to give mesh analysis another go, and see where that gets me.
[DOUBLE EDIT] Mesh analysis didn't get me anywhere :(
Im tearing my hair out over this problem, so any help would be ...
-5
votes
1answer
58 views
How to build a switch that is turned on with small voltage? [closed]
I want build a switch that is switched ON with 1 or 2 volts. A small circuit would be fine.
0
votes
3answers
108 views
A device that wirelessly, securely posts to a server in response to door opening: off the shelf or custom-make?
I am looking for an off the shelf component for a project I am currently working on. Due to the nature of the project I cannot go into much detail about the project itself, only give a high level ...
2
votes
3answers
125 views
Checking materials (cheapest possible) to be used for a solar dark-detecting LED light bulb circuit
I want to make this circuit, which includes a joule thief:
It's for a solar dark-detecting LED light; and I'm trying to follow this guide: ...
4
votes
3answers
235 views
Solving this op-amp circuit
I would appreciate some help solving the following circuit. I've been trying for a very long time and can't get the same answer the book has. I'm trying to get \$ V_o \$ in terms of \$ I_{os} \$.
...
2
votes
1answer
68 views
Simulating step function in PSpice
How do I implement the the function:
\$V_s(t)=1.5u(t)-3u(t-.01)+1.5u(t-.02)\$
in Pspice? I know to use the VPULSE source but it has only two voltages as parameters but I need 3.
0
votes
0answers
51 views
Branch impedance matrix definition
I know what mesh & node impedance matrices are, but what is a branch impedance matrix? Google is not helping me find a definition. I presume the branch admittance matrix just contains the inverses ...
1
vote
2answers
231 views
Help verify 8x8x8 LED cube circuit
I am a beginning hobbyist when it comes to electronics. I have read lots of theory but I only have a little bit of hands on experience. I would like to build an 8x8x8 LED cube and I came up with this ...
6
votes
3answers
238 views
Why is S=1, R=1 state forbidden in RS flip flop?
I have come across the RS flip flop & I have tried implementing that on a simulator & using actual logic gates. But I'm still not sure whether I have correctly understood the unstable or the ...
5
votes
2answers
163 views
Solenoid Driving Circuit
I'm trying to drive a 12v (14W) solenoid and have problems figuring out the components for the driving circuit.
The solenoid draws about 1.166A and the MCU is being operated at 3.3V.
I've seen many ...
-5
votes
1answer
98 views
What is the output for this sequential circuit? [closed]
For this sequential circuit
are the outputs "next state function" for q1 and q0?
$$D1 = (Q1)Y' + (Q0)Y' $$
$$J0 = Y'(Q1)' + Y((Q1)'+(Q0)')$$
$$K0 = Y$$
$$Q1 = D1$$
$$Q0 = (J0)(Q0)'+(K0)'(Q0)$$
7
votes
5answers
519 views
Why doesn't the relocation of this resistor affect the circuit's total resistance?
Why does moving the 470Ω resistor in these examples have no effect on the total resistance between A and B?
This is a new question regarding the answer given here by @helloworld992.
2
votes
1answer
110 views
How to calculate a simple mixed parallel/series resistor circuit
I'm trying to understand how to calculate resistance in simple mixed parallel and series resister circuit. Below is a question from a worksheet I've been playing with to better understand the topic ...
2
votes
3answers
146 views
Ground on Breadboard
I need to connect an input signal from a function generator to a circuit I made on a breadboard.
If I use a BNC to Banana cable, then would the "ground" of the function generator (the ground on the ...
2
votes
1answer
60 views
How to detect and identify multiple points of contact
I am looking for a way to detect & distinguish multiple points of contact from force or pressure. I have asked a related question at the URL listed below:
How to encode a large number of digital ...
0
votes
1answer
95 views
How to implement a delay OPTOcoupler input there by the circuit remain on for the next 1 second
I have another new project , the project is simple one when a call lands to the mobile an ac machine is triggered and it turns off when the mobile ring stop , for that i have used this circuit
The ...
1
vote
4answers
147 views
Smallest circuit to make a sound
I'm looking for the smallest circuit to make some noise. This sound has to be constant and annoying, it's intended for the alarm on a timing device. Any ideas?
The circuit will be triggered with a ...
