Analog circuits have a range of voltages, rather than just two as in digital logic.
4
votes
1answer
111 views
DIY Inductor: Solve for number of turns without knowing the length?
I'm trying to wrap my own inductors (air coil) for an RF circuit that I am making and I am having a little trouble solving for the number of turns I need to reach the desired inductance.
...
6
votes
8answers
343 views
Isn't current flow a wrong term?
In most text books and other electronics material it's said current is flowing through the circuit. Isn't this wrong? As current is flow of charge. Is there anything such as flow of flow of charge?
-4
votes
1answer
149 views
What is the working of Class A , ClassB and Class C amplifiers? [closed]
Please describe conceptually the working of Class A, Class B and Class C amplifiers.Having problems understanding them.
-2
votes
4answers
95 views
What are power amplifiers?
What is a power amplifier? what is the difference between power amplifier and simple amplifier? As both are amplifying the signal what's the difference?
4
votes
3answers
147 views
Voltage divider Biasing of transistor
In this amplifier circuit we are using a voltage divider bias. Why can we consider that voltage produced by R2 is actually providing voltage to the base. What is R1 doing?
5
votes
2answers
488 views
What is Q-point of transistor?
What is the Q-point of a transistor?
Why it is needed?
How can we set this Q-point of transistor?
Please explain it as I am having difficulty understanding this concept.
4
votes
2answers
98 views
Connecting Analog Signals Between Boards
When you have a sensor with an analog output on one board, and an analog-to-digital converter (ADC) on another board, what's the best practice in connecting them together? For example, if you have a ...
0
votes
1answer
38 views
Considering Loading in analysis and design
What are the conditions under which loading can or cannot be ignored? I would like to be able to design a circuit in segments and then connect these segments together to create a circuit that performs ...
5
votes
5answers
205 views
How to recognize the type of analog filter given its topology?
Having trouble to tell what kind of filter (Low-Pass, High-Pass, Band-Pass, Band-Reject(Notch) are present given a topology in cascade.
In the following picture I see 3 stages, is this ok? (2 active ...
-1
votes
1answer
30 views
High voltage peaks when using mxo45hs-3c-1m0000
I am using an mxo45hs-3c-1m0000 quartz in order to produce a 0-5V square signal (1MHz). On the oscilloscope, the signal I get is a square signal, but there are important sine waves in the plateau. I ...
0
votes
1answer
50 views
Need faster analog mux. Use switches and summation amp?
I need to alternately sample 64 channels at 20Ms/s. That's 50ns per channel. I used to have a slower version at 2Ms/s and there i used 1 ADC and a series of analog muxes. This time around, at ten ...
1
vote
0answers
89 views
Lighting relay(?) with 220V leakage insensitive coil
Existing staircase lighting time-automat can not use 220V neon mini-bulb or LED lighted make-contact buttons. - These convenient buttons cause it t false-start (as if pressed) due to their ...
2
votes
2answers
390 views
Role Of Emitter (By Pass) Capacitor
What is the importance of Bypass capacitor of Common-emitter amplifier? Will the gain be reduced when it is removed?
5
votes
2answers
134 views
Will checking the backup voltage on an RTC drain it's backup battery?
I'm working on an ATMega project that will be keeping time and I'm trying to make it so you have an option of either software time (millis() based), DS1307, or DS3231 (ChronoDot) RTCs.
At the most ...
1
vote
2answers
132 views
Simplifying a circuit to measure current
So I'm to calculate the current in the places I put the ammeters in (yeah, I reckon one of them is turned around :)):
And while I can calculate such things for series or parallel circuits, I was ...
1
vote
2answers
67 views
Will a device capable of receiving a 200 Vrms input signal happily accept a 200 VDC signal?
To the best of my knowledge, Vrms is used to express an AC signal as the equivalent DC signal that would produce the same power dissipated in a resistor R; I believe this is best calculated using a ...
2
votes
1answer
121 views
Single Supply Op Amp Bypass Caps
The output stage of my circuit is a 2nd order inverting low pass filter. The input should be negative (DC), thus yielding a positive output (DC). It is possible that the input could be positive, but ...
8
votes
2answers
235 views
Wilson current mirror
I built a super wilson current current mirror. The Iin is 4-20mA at 24Vdc. Iin to Iout accuracy was a really bad 5%. I put 100 ohm resisters on the source to ground, and that helped a little. How can ...
3
votes
1answer
203 views
Is an ADC always necessary between 8051 and zero crossing detector?
I am making a SCR(Thyristor) trigger by using 8051 microcontroller.
I have a here is a zero cross detecting (ZCD) circuit which detects the zero points and this is conveyed to the 8051 which will do ...
2
votes
2answers
99 views
Analysis linear ladder circuit
I'm trying to answer following question:
In the ladder circuit in figure 3, find the current, I, if \$V_s = 7V\$.
Use the fact that the circuit is linear. This can be done by assuming that ...
1
vote
3answers
147 views
Parallel resistor not affecting rest of the circuit
I have been asked the following question:
The resistance, r, is not known in fig(1a), why does its value not affect potential at b?
By Thévenin's theorem, any arbitrary voltage source can be ...
2
votes
1answer
174 views
Reading analog input pic18
I'm trying to read an analog input on a PIC18F65J11, and I'm having trouble. I don't think the pin is set up correctly because I'm getting a 0 for the value I read in, and the input is measured to be ...
2
votes
2answers
138 views
IR Reflectance Sensor for a Wheel Encoder - Analog or Digital?
I'm in the process of building wheel encoders for my robot and have come across 2 different IR Reflectance sensors.
Analog
Digital
I'm trying to find out what the potential benefits or drawbacks ...
2
votes
1answer
111 views
Analog vs digital wireless newbie questions
As i try to understand the real difference between analog wireless and Digital wireless i'm asking some questions :
As far as i know digital means more accuracy of data, but require larger bandwith to ...
0
votes
1answer
140 views
Increase the analog sample rate of the IOIO?
On the analogue input wiki page for the Sparkfun IOIO (android development board), it says that the analogue pins are sampled at 1kHz. This is too low for a number of potentially exciting uses, like ...
0
votes
1answer
117 views
what is the difference between sample method and sample and hold method
I want to know what is the difference between sample method and sample and hold method ,and why are these two methods important to study analog to digital conversion and its reconstruction back to ...
3
votes
2answers
186 views
PID to control turntable speed?
I recently got a Technics turntable and the belt that came with it is super crappy and makes the platter hickup when it passes by the seam on the belt. This is not audible, but it got me thinking ...
6
votes
3answers
267 views
Convolution perfomed by an analog circuit
As a Electronic Engineering student I have a fair knowledge about convolution and DSP. But, I was wondering if it is possible to perform a convolution only using analog circuit (without memory)? And ...
0
votes
1answer
124 views
Designing a PoE Circuit
I'm going to buy a PoE injector kit, and I will supply it with an AC voltage, and with ethernet cable, and at the other end I will design a seperator circuit, but however most PoE injectors just give ...
3
votes
1answer
251 views
Low-pass filter on microcontroller output
I'm producing a signal which contains 7 frequencies using a microcontroller with a DAC. the frequencies are 16.5kHz 16.7kHz 16.9kHz 17.2kHz 17.4kHz 17.6kHz 17.8kHz. and sampling frequency (at the ...
2
votes
4answers
201 views
Frequency shift
I'm trying to generate a signal which contains only several specific frequencies I know of in advance, around (16.4kHz, 16.7khZ, 17kHz,...)
the signal is generated using a microcontroller, which then ...
1
vote
3answers
194 views
ADC: Need to convert 10V-32V(from battery 0-32V) range to 0-5V
I need to convert 10V-32V range from a battery ( full range 0V- 32V) to a range of 0-5V before applying it to ADC.
This is basically to get more resolution in my required range(10v -32V), since most ...
4
votes
2answers
240 views
Removing DC wander in the offset of a DC-biased audio signal
I'm trying to read an audio signal from an Android phone as a serial input to an MSP430G2553, adapting this design to use the MSP430's onboard comparator module instead of an LM324. The Android code ...
0
votes
1answer
184 views
USB ground on MSP430 Launchpad interfering with Comparator_A input voltage
I'm trying to read an audio signal from an Android phone as a serial input to an MSP430G2553, adapting this design to use the MSP430's onboard comparator module instead of an LM324. The Android code ...
1
vote
2answers
123 views
converting lots (100+) of analogue audio sources to RTP/UDP/'IP packets'?
I was 50/50 posting this here or another board.. hopefully it's in context and maybe I can get some help!
Basically I have a scenario where I'll have just over 100 analogue audio sources (50 in and ...
1
vote
2answers
337 views
Arduino shows voltage drop, voltmeter doesn't
I'm totally lost with the behavior of this simple schematics.
Once the charging process starts, Arduino's voltage reading becomes very different (should I say wrong) from the one voltmeter shows, as ...
-2
votes
1answer
239 views
USB webcam to composite video via Software? [closed]
I need a way to convert digital usb signals from a webcam into composite, analog output in real-time. Is there any software that could do this?
3
votes
2answers
132 views
Is it still possible to find Braun Lectron System around, or equivalent ? [closed]
Is it still possible to find Braun Lectron System or equivalent around ?
For thos who don't know about it : http://www.decodesystems.com/lectron.html.
It is basically analog building blocks that did ...
1
vote
2answers
82 views
Using a vintage US touchtone phone on a the Swiss ISDN network [closed]
I have one of these phones (US touchtone phone from the '70s):
and would like to use it in my house in Switzerland where the phone system is ISDN. My electrician told me it can't be used here, but ...
5
votes
2answers
228 views
False Positives on Arduino Input
I've used analog and digital input for a multitude of applications with the Arduino Uno board. It has continuously given extremely non reliable readings, where the analog input is always fluctuating, ...
0
votes
1answer
166 views
Video Composite signals
What are the considerations for PCB layout, and connector selection for video signals. Is it necessary to follow 75ohm impedance criteria in a closed system. The pipeline starts at Sony FCB IX 11 A ...
2
votes
1answer
1k views
How to read data from a 3.5mm headphone jack?
I was searching for a way to read data from a 3.5mm hack using an Arduino, but I couldn't find a well-detailed, beginner-friendly, tutorial on how to make this, at least how to wire everything and ...
5
votes
3answers
156 views
How are Zener maximum power ratings derived?
Im having trouble to understand how some of the maximum power ratings of Zener regulators are derived, I understand that Zener voltage will be dependant of current Iz, but take this for example: ...
3
votes
1answer
73 views
Is there a solution for keeping circuits with low frequencies small?
background
I'm essentially making an mixed-signal/analog computer(to accelerate certain mathematical operations). I'm looking to create many AC filters (of different types) at low frequencies (sub ...
8
votes
1answer
223 views
Cassette Input From TRS-80 - Design Review
I'm working on getting an input from a cassette for a TRS-80 microcomputer (of 70's vintage). This is what I've worked up. It is a second order high pass active filter with rolloff frequency of 2kHz ...
0
votes
1answer
80 views
Purpose of negative bias reference generator
I am working on a redesign and there is a negative bias generator on the ADC in the circuit. (not the circuit below) I am pretty sure that the small negative voltage instead of ground is there to ...
4
votes
4answers
242 views
How to calculate permittivity of a fluid
I am confused about calculating permittivity of a fluid. Permittivity differs from one fluid to another.
$$\epsilon=\epsilon_r\epsilon_0$$
Since it is an electrical property combined with an ...
4
votes
1answer
274 views
Limiting, scaling and biasing analog input (ADC) of microcontroller
I have current transformer coils to monitor a gas-powered AC generator output (A & B) and 4 load circuits.
The output of the T1 coil with a 1500 watt load is about 30Vpp.
Will this circuit ...
-3
votes
1answer
79 views
Microcontroller
A c515c (8 bit A/D) has the following parameters
Fosc= 11 mega hertz , Vagnd= 0 volts, Varef= 4 volts
What is the +_1 bit round-off % for a 3 volt, measurement?
1
vote
3answers
784 views
How can I reduce noise from an analog signal from an Arduino?
I am trying to read an analog signal from an Arduino board through LabVIEW.
The sensor is an infrared phototransistor, which I have connected in reverse bias (20k resistor) to an Arduino pro mini ...
