# circuit

1. ### SMD Capacitor selection

Hello everyone, How can we calculate the voltage rating of an SMD ceramic capacitor. Is it dependent on the package size?.
2. ### LTspice ECG

Hello. Thank you for clicking on my article. I'm from Korea and a college student. I'd like to find a solution. My circuit simulation speed is too slow. So I want to speed up. I saw what other people did at Google and made it. I want to speed up the simulation. I'd appreciate your help.
3. ### 0 to 9, 9 to 0 counter

Hi there, got a serious problem about Counters. i have to create "a circuit that counts from 0 to 9 then from 9 to 0 using two separate counters" and "must consider BUS concept". i used two 74192 and two 74153 Multiplexers ( for BUS ), one of the counters is ascending and another one is...

5. ### If you can Help! ?o design an Automated system

I need to design an Automated system such that a user gives inputs in 3 bits and there's a clock running that resets itself and gives a positive signal after the time indicated by input. We can use logic gates, combinatorial circuits, sequential circuits, counters, registers.
6. ### How to make a momentary switch deliver a pulse on one circuit, while also closing another circuit until it is pressed again

It has been over a decade since I've done anything circuit related, and I found out the hard way that I have forgotten basically everything. I am trying to make a buttonpanel acting as an input interface for PC using an arduino. I want to have 32 different momentary inputs in a 4x8 matrix. My...
7. ### lm386/why this circuit works well with my iphone audio jack but when i connect a mic it makes so much hiss and noise

as you can see this is the circuit that I made based on lm386N-1 whenever I connect my iPhone (it's a 5s if it makes any difference ) the sounds works great and clean only when I put it to max it has some distortions but when I connect the electret microphone it makes a lot of noise and hissing...
8. ### Charging Li-ion circuit

Hi, I made a circuit that charge Li-ion battery. When I simulated it, I found something strange; the time for charging was too short. I made it with 'LTspiceXVII' and here's my circuit's diagram and the graph, also I uploaded the 'Li-ion bat file'. So, would you like to help me if you don't...
9. ### Soldering dead bug circuits

Hi there, I have been working on an AM radio test generator. It is from the book ”building your own transistor radios”. I would provide a schematic of the circuit although I believe the copyright would prevent me from doing so. The two ICs used in the circuit are the 74HC14 hex Schmidt...
10. ### Need help with DC-UPS

I need an DC-UPS that can handle at least 300W, but I couldn`t find anything. So I come up with this: Battery: 4s2p Li-ion (3.7V) PSU: 14.8V P-Channel MosFET: IRF4905 (maybe? idk) N-Channel MosFET: idk Will it work? What should I change? Do you have any UPS suggestion? Thanks!
11. ### VHF oscillator circuit w/ large frequency range and change according to capacitance value

Hello, It's my first post. I'm new in electronics fields. I'm french and my english is not very good, excuse me. I want to make a VHF oscillator(~ 30 MHz) that his frequency can change with the value of the capacitance. I found in an another post the RF2506 which seems to works but it's...
12. ### Confirming Circuit Configuration.

Hello, I am in a research team and is designing a circuit system for powering a motor with battery and supercapacitor. The battery and supercapacitor powers the motor separately and the motor gives regeneration power back to the supercapacitor (motor driver allows for regen). Can experts in this...
13. ### Bodeplot of simulation and network analyzer difference in magnitude with same characteristics

Hello, I have a problem which I can't find the solution. It's related with the determination of the bodeplot of a circuit. According to my bodeplot in the simulation, the flat part of the magnitude plot is -23.02 dB (Simulation.PNG) and the cut-off frequency is equal to 17.67 MHz whereas the...
14. ### How to design a BJT Tansistor Amplifier with voltage divider biasing

I'm not sure if this has been posted somewhere before, but I can't find anything that really addresses this type of a problem. For college we need to design an amplifier circuit using a transistor, this is not that bad. The problem is that there is no proper explanation that I can find of where...
15. ### Ability of PLC's to communicate via 4-20mA and 0-10volts between laboratory devices and the PLC

Hey guys, I'm studying electrical engineering technology and the Coronavirus turned my capstone project into a research paper. My assignment is on PLC's, which we have covered the basics of, but I still know little about how they operate. Here is the prompt: "Research the ability of PLC's to...
16. ### Diagnosing/repairing a Laptop motherboard?

Hey guys! First time posting here! I have an Alienware 17 R3 laptop that I picked up broken to see if it was repairable (I like learning new skills). All signs point to a short on the motherboard, I plugged in the charger and the blue LED on the charger cable goes out immediately if I attempt to...
17. ### Circuit Breaker Location

Hi, in IEEE 3 bus, why are circuit breakers connected at the 'load' rather than connected at the 'generator and load'?
18. ### Triangular signal cutting off

I made a circuit to demonstrate the work of a 555 and a constant current regulator and wanted to add triangle wave input. I've done that by integrating the output of a 555 timer, and at the node 'tri' I do get the desired triangle wave of ~ +-8V. Since I want the the voltage positive at all...
19. ### Connecting 12V Inductive Sensor to Raspberry Pi 3B+

Hello, I am not too strong with building electrical circuits so I am just wondering if I could get some feedback on the circuit I built. I am trying to connect a 12V inductive sensor to a Raspberry Pi 3B+ 3.3V port. The inductive sensor is being used to detect a metal sleeve inside of a valve...
20. ### Arduino Motor Circuit Only Getting Less Than 1V

Hello, I have built this motor circuit for my Arduino and when running it only gets less 1v and the motor spins very slowly and my bigger motor doesn't spin at all. I have attached the diagram that I followed below. The Motor should be getting 5v from the Arduino although something seems to be...