The circuit-design tag has no usage guidance.
-3
votes
1answer
51 views
modifying a frequency counter to make it a frequency meter [on hold]
Is it possible to modify this circuit and make it a frequency meter? This is an assignment and none of us know how to do that. We all have considered to make another circuit and not modify the one ...
0
votes
1answer
11 views
circuit explanation for detecting different gases by mq2 with raspberry pi [on hold]
I am able to get the readings from mq2 sensor but don't know how to detect different gases by it.
Can anyone help me in getting the circuit explanation of detecting different gases by using mq2 ...
-1
votes
0answers
17 views
Best PWM IC for LED Driver [on hold]
I am confused to choose best PWM IC for my LED bulb Driver (Offline flyback SMPS converter with primary sensing)
Specification-
Input-90v to 265v AC
Output- 150mA constant current, 40V DC
Please ...
0
votes
0answers
35 views
Circuit confusion help
Can someone help me understand this circuit. I'm confused how both 5v and 12v are connected to same transistor Q63. Is 5/12v flowing through the same circuit when it's turned on? Or is Q63 simply ...
0
votes
2answers
38 views
Drive a capacitance load with a very large output resistance analog voltage source
I have a signal source with a very high output resistance. The output of this source is connected to the input of comparator. Actually the input capacitance of comparator is not large (about 20fF). ...
0
votes
3answers
77 views
Are there better alternatives for these buffers?
I'm building a circuit that extract the DC component of an input signal, ,divide the DC component by 5, and finally add 2.5V it.
Here is the schematic of the circuit (the last op-amp is to invert ...
0
votes
2answers
77 views
Microcontrollers and custom boards [closed]
I am new to electrical engineering and the usage of microcontrollers. I am trying to build a custom circuit board using parts bought separately, but I'm not sure how this should be done.
Some things ...
-3
votes
0answers
51 views
Design of a two stage BJT amplifier (CE-CC) [closed]
Hi guys, I need to design a circuit and find the values of the components. There are 2 ZTX650 npn bjts. It has to be designed for an 8 ohm load which has to be driven with an output signal of 1 v ...
0
votes
1answer
40 views
Electric Bell Quiz with IC
I have a quiz bell circuit electrically. When one bell is pressed, the LED will light and bell other will not work.
The problem is when bell is pressed simultaneously, then the other LED will also ...
1
vote
1answer
69 views
How come SMPS regulators doesn't show current limiting circuit?
for example the LM2678-ADJ is a famous buck converter, there are also many others. I have googled and looked through other regulators, there are many schematics in the datasheets of how you make the ...
-3
votes
0answers
34 views
Designing an amplifier withBJT [closed]
Design the circuit shown in the figure by calculating the values of R1, R2, R3 and R4. 2N3904 NPN transistor is to be used. In this design the bias voltage between emitter and collecter should be 5V ...
0
votes
0answers
40 views
Systematic procedure to implement a transfer function [closed]
What systematic procedure should I follow in order to design a circuit that implements an arbitrary Frequency Response/Transfer Function.
And by "arbitrary" I'm not referring to common functions ...
0
votes
5answers
124 views
High peak current supply circuit
I need to design a "peak" power current supply circuit for my load. Power specifications of load are below;
Continuous power consumption: 12 V 5 Amperes DC.
Peak power consumption: 12 V 10 Amperes ...
1
vote
2answers
58 views
What does the open circle in the circuit depict?
The open circle at pin 4 in 555 and pin 13 in 4017 has got me confused. I'm new to electronics and any help will be appreciated.
Also does the pin 5 in 555 need to be connected to pin 12 in 4017?
...
0
votes
2answers
50 views
Circuit that adds offset if input voltage is negative and subtracts offset if input is positive
I'm trying to build a circuit that will have an input DC signal. I know there is a stead DC offset in the signal, and want to subtract it. I do not know if the input signal is positive or negative. If ...
1
vote
2answers
43 views
How to provide external power supply for 8 servo motors?
When ever I switch on the power supply there is not enough power supply to servo motors. Voltage across each servo motor is 1.5 Volts only. Should the circuit must be changed?
Is there any better ...
0
votes
1answer
37 views
What is the best method to determine bypass capacitors for each chip in Mixed-Signal Systems? [closed]
In datasheets of chips, usually they have reference designs and to those designs bypass capacitors are predetermined. But, when I examine some high level designs of those chips I see different bypass ...
-2
votes
0answers
14 views
How to create a gate circuit using ITC99 benchmark circuit?
I wanted to create a sparse matrix from a electronic gate circuit to test my BFS(Breadth First Search). I figure out that many researches are using ITC benchmark circuits( ...
1
vote
2answers
54 views
MOSFET as a VCCS or an variable resistance
I am a bit confused. In saturation region, sometimes, an MOSFET is called voltage-controlled current source and sometimes it is called variable resistor where its resistance is controlled by the ...
0
votes
0answers
28 views
Stick Diagram for D Flip Flop
I am new to Cadence and I am trying to design a D Flip Flop with asynchronous reset.
However, I am having trouble with drawing the Stick Diagram from Euler's trail.
My flip flop is designed this ...
0
votes
2answers
82 views
Resistor for 20 LED's in series
I am reverting here for some advice on a LED panel circuit that I am trying to build as I cannot find any concrete answers anywhere else online. My apologies as my understanding of electronics is very ...
1
vote
1answer
112 views
Are there any circuits to get output as a sum of a set of current sources?
I have 3 current sources (I1, I2 and I3) and I need to get an output of linear summation of the current of these sources.
Iout = aI1+bI2+cI3
where a,b and c are gain factors (like 1 to 10 and are ...
1
vote
1answer
45 views
What are the capacitor values and why there are holes in PCB? - Semtech's reference design - SX1272MB1DCS
Semtech is providing a reference design concerning the SX1272 chip:
SX1272 modules: SX1272MB1DCS - 868 MHz - Combined RFI and RFO, switchless (Ref design only)
I can't find the values of C12, C14, ...
-8
votes
1answer
38 views
How can I build a monostable multivibrator (one shot) using 74LS123?
how can I build a monostable multivibrator using 74LS123? with 10 microseconds of pulse.
please help
-6
votes
1answer
42 views
0
votes
1answer
78 views
your common calculations as professionals [closed]
Going a step further from my previous question regarding how EE's skirt around doing a lot of basic calculations, I wanted to know beyond ohm's law and calculating voltage dividers (just using those ...
2
votes
1answer
52 views
What's the purpose of this RC filter?
The circuit is the following and i think this RC filter is used for anti debounce purposes but i'm not sure. Is it to prevent the optocoupler and the indicator LED from being "damaged" by the debounce ...
0
votes
1answer
55 views
How can I build a dual potentiometer?
I am about to build a wien bridge oscillator circuit which is shown in the figure below:
However, I need a dual potentiometer to do so, because the resistors VR1a and VR1b must have the same value ...
0
votes
0answers
52 views
MIC2251 Boost Converter Voltage Dropping
I have put together a boost converter using the MIC2251-2YD5, SOT-23 package.
http://docs-europe.electrocomponents.com/webdocs/1065/0900766b81065118.pdf
I am using to to get 5V from a single cell ...
0
votes
2answers
61 views
RC controller design for small car
I am creating a small car that is to be controlled by a small hand held joystick remote.
basically I am trying to find the best option for doing this task.
The vehicle has two 24V motors, one for ...
0
votes
1answer
87 views
The Tao of Transistor Biasing [closed]
I think I understand the principle of transistor biasing but i'm a bit lost on forward vs reverse biasing.
Can an EE look at a schematic and tell the biasing of a transistor--reverse/forward?
Or is ...
1
vote
3answers
92 views
How should I control distortion in an op-amp circuit? [closed]
I understand that this is done via feedback, however, some clarification regarding techniques and considerations within the feedback portion would be helpful.
0
votes
1answer
64 views
Lithium protection circuit design
I am trying to design a protection circuit for a single cell lithium battery, and I was hoping for some advise on what things I need to consider.
So far, my thoughts are to provide low voltage cutoff ...
2
votes
2answers
44 views
Gain or amplification
I need to amplify a 5 to 50 mV signal to 0.3 to 2 Volts over 20hz to 40k. Or at least that's the range I'm concerned with. What about an op-amp spec tells me if it can do this? Can you please provide ...
0
votes
0answers
41 views
Electronic clapperboard
I hope someone might offer a novice some advice and send me in the right direction.
I'm trying to build a circuit that I can use for synchonsing cameras (an electric clapperboard if you will).
I ...
0
votes
1answer
83 views
Chess-Board schematic/pcb layout
Hey guys as described here I also want to make a chess board with some arduino support.
Here I want to ask some questions regarding the schematic and the pcb layout I am planing to do. @Dmitry ...
0
votes
1answer
36 views
Glowing two leds alternatively in a given ratio of time
I want to design a circuit for glowing two leds for alternate intervals for different input voltages.
For example:
Consider two LEDS Red and Green. When the input voltage to the circuit is 0-5Volts ...
0
votes
2answers
62 views
Multi-stage differential amplifier
What is the purpose of combining two differential amplifiers as in the figure below? The first differential amplifier is a single input balanced output and the second differential amplifier is a dual ...
-11
votes
1answer
63 views
Mobile signal jammer [closed]
I am trying to make a mobile signal jammer for GSM 900 and GSM 1800 using this circuit . Actually I am having doubts regarding antenna . What type of Antenna can be used . I tried using copper and ...
-3
votes
1answer
95 views
How do I build a Circut to create temperature changes in LEDs? Looking for a range of 3000 to 6,000 for photography? [closed]
I see commercial lights for photography that can change color in the range of 3-6,000 or tungsten to daylight values. These are not arrays of three RGB lights but rather single LEDs and the ...
1
vote
3answers
109 views
Protection For This Circuit
This is my theoretical (haven't tested yet) circuit I have designed for a project of mine.
Electrics is a new field for me so please raise flags if my circuit has flaws.
Assuming the circuit is ...
-2
votes
1answer
72 views
3 Amps and 5 volts needed but don't know how to obtain
I am creating a circuit that detects ozone gas. The gas sensor requires a 5 volt supply and at least 3 amps. How do I get these amounts using batteries? I have researched how many amps different ...
0
votes
0answers
21 views
Conventional dynamic comparator
Here (page 2) is a conventional dynamic comparator. I am wondering about function of M3 and M4 here. Could anyone explain that?
0
votes
2answers
62 views
What is the circuit for the Singing doll that start when touching hands
If you look at the Elsa singing doll toy, it trigger the music/singing when you touch both hands.
Also, this toy can stay inactive for months on only 3 little battery
I am assuming they are ...
0
votes
3answers
80 views
Input/output impedance of microcontroller
how to calculate the input and out put impedance for a micro controller , for the purpose of modeling in LT spice ,
for example RX610 family from Renesas
For example the lumped characteristics can ...
0
votes
1answer
76 views
Arduino Bell Detector (Unsafe circuit)
I currently have a circuit that the arduino pro mini checks is the button pressed, the relay will be closed to trigger the bell alarm. And a UDP Packet will be also sent to a server to notify me.
...
1
vote
0answers
49 views
why is it necessary to have R1 //R2 >> Rg in an common source amplifier?
Lets say you're given:
Why is it necessary to have R1//R2 >> Rg?
Rg is the signal source resistance of the oscillator
is it just to neglect Rg in the calculations?
4
votes
3answers
757 views
Single wire USB
I wanted to convert a USB differential signal into one signal, and then send it over one wire, and then restore in back to differential signals at the other end. I wanted to do this for a USB 1.1 ...
0
votes
0answers
41 views
Making my Atmega128 board AVR headers
I have been working on this project for days. Finally got the framework, ie, the header for this 64 pins MCU up. I have few questions, or rather doubts before finishing it up.
Being new to this IC, ...
0
votes
3answers
62 views
Delayed latching switch
How would I make a switch that is controlled electronically, and has a ten second delay?
I have a circuit that will output either 3.3V or 0V. I would like to make a circuit that detects 3.3V, waits ...
