A device or circuit that generates an AC signal at a certain frequency.
2
votes
1answer
78 views
What is return current of crystal oscillator?
I belive that every signal on the PCB has its return current. One layout hint for crystal oscillator is that "The ground connection for the load capacitors should be short and avoid the return ...
4
votes
1answer
115 views
Why use capacitors with crystals?
Whenever I come across crystals used in any of MCU or Processor, whether it be 32.768 kHz responsible for Real Time Clock or 25 MHz crystal required for clocking different interfaces connected with ...
1
vote
0answers
27 views
stm32f2xx HSI configuration does not work correctly
I'm using below settings (in SystemInit function) to configure a STM32F215RG MCU to work at maximum speed (120MHZ) with USB support:
...
3
votes
0answers
56 views
Ramp/Pulse VCO - hot change the frequency?
I've successfully built this VCO circuit using an LM13700 that works just fine if the VC (the 510K resistor) is not connected to anything. Needless to say, I'd like to be able to change the frequency ...
0
votes
2answers
70 views
Is a negative resistor a superconductor that does not require being cooled down to get 0 resistance?
Title explains it, is it possible to create a superconductor using negative resistor oscillator / amplifier? As superconductors are conductors with 0 resistance. Isn't an amplifier a superconductor?
...
3
votes
2answers
77 views
How to Set up an Oscillator For Simple Frequency Generation [duplicate]
I ordered a bunch of these 8mhz crystals: http://www.amazon.com/gp/product/B005PSXEQ4/ (they sent me 13mhz instead though, no big deal...)
I just got them to experiment with.
I assumed they only ...
4
votes
1answer
132 views
Homebrewed phototransistors - unijunction versions
Back in the days, when phototransistors were hard to get (especially in some parts of the world like the communist eastern block), one could brew their own by just filing/sawing off the top of a TO 18 ...
3
votes
1answer
73 views
How does the Accutron Spaceview work?
I am wondering how the electronic circuit used to drive the tuning fork in the Accutron Spaceview watches worked? The page The Accutron 214 gives a brief explanation and some diagrams. I am most ...
1
vote
0answers
105 views
How to Isolate Low Voltage Control Circuit from High Voltage Power Circuit?
Didn't have a lot of success google searching...
Can anyone give me a brief run-down of some methods I could use for this?
I want to drive a MOSFET or BJT with a 12v 555 circuit or oscillator. ...
3
votes
1answer
107 views
Is this a certain kind of oscillator?
I was having a ton of trouble understanding oscillators, and I needed something to power a tank circuit at its resonant frequency.
I decided to just come up with something myself and this is what I ...
0
votes
1answer
52 views
VCO - sawtooth and duty cycle?
I've successfully built a VCO using an LM13700 OTA. The circuit generates square and triangle wave. I wonder if I can add a couple of diodes and a potentiometer to be able to skew between ...
0
votes
1answer
116 views
Oscillator circuit
I'm trying to solve this problem for some hours now but without success, I thought I would ask for help here. I detailed my doubts in the image below :
3
votes
3answers
329 views
Why does an Oscillator produce sine waves?
By the definition of Oscillator: 'An Electronic circuit that produces a repetitive, oscillating electronic signal, often a sine wave or a square wave' I'm familiar with RC Phase Shift Oscillator and ...
4
votes
3answers
274 views
How to connect 4MHZ crystal oscillator to get 16MHZ
I've 10 4 MHZ crystal oscillators. I need a 16MHZ clock signal. Can I connect multiple 4MHZ oscillators somehow (serial, parallel) to get 16MHZ?
0
votes
1answer
82 views
Building a cheap and stable microwave network analyser or oscillator (2-5GHz)
I am interested in measuring the changing dielectric constant of a liquid as it undergoes a process. My background research of scientific articles shows that the 2-5GHz range provides the best ...
1
vote
1answer
76 views
Twin T circuit noisy
I've been fiddling with a twin-T percussion oscillator with success. It's built on a breadboard and it sounds exactly how it should sound (damped sine wave, big 808/909-kind of kicks). However it's ...
2
votes
2answers
127 views
What is the highest frequency possible to be generated with electronic circuits
First, its sound oscillators for low-frequency audio waves. Then Radio wave oscillators varying from low frequency AM to high frequency Cell-phones. Then microwave oscillators in the giga hertz. What ...
3
votes
3answers
273 views
How to build an accurate oscillator around 1 kHz?
Is there a way to build an accurate oscillator producing a sine wave for a single fixed frequency in the 500 Hz - 5 kHz range, using relatively common components?
Any frequency within this range ...
-1
votes
1answer
416 views
Op Amp based Colpitts oscillator
I have designed an op-amp based Colpitts oscillator in multisim. When I press run button it shows- "timestep too smaall error". I've googled and tried everything but it still shows the error.
The ...
-3
votes
1answer
118 views
having problem in creating 555 oscillator in breadboard [closed]
i am quite new in electronics department and so have a very little knowledge about it...ok so i am going to set up a 555 oscillator.....i have the 555 timer chip, a solderless breadboard and resistors ...
1
vote
1answer
272 views
How to design an Oscillator Circuit (500 MHz range) with no Op amps?
I am trying to design an Oscillator circuit which can produce a good sine wave with a frequency of at least 500 Mhz. This is for RFID applications. I have tried to use an class E oscillator, but i ...
1
vote
1answer
67 views
DS1077 to drive a PIC's clock
I found the DS1077, a "dual-output, programmable, fixed-frequency oscillator". I was wondering if it would be possible to let this chip provide the clock signal for the PIC(18F46K22) that operates the ...
3
votes
2answers
167 views
What's wrong with this Phase Shift Oscillator?
I am trying to design a phase shift oscillator, using a CE Amplifier.
I have a Vc of approximately 6V, gain of approximately 40(>29, as required).
I aim for an oscillation frequency of 1.5 kHz.
But ...
1
vote
1answer
162 views
Will an IC that requires an Oscillator work without one?
I have a PL2303HX and I just etched my board with a USB to Serial IC (PL2303HX). The problem is that it requires a 12 MHZ crystal but I don't currently have.
Just a side note, the IC is on the same ...
2
votes
0answers
73 views
PIC16F877A latchup/glitching
I have a PIC16F877A microcontroller with a 19.6608 MHz crystal, wired for 12V ICSP. I can reprogram the chip just fine, and it runs almost flawlessly (it's blinking an LED right now as I type). Only ...
4
votes
4answers
377 views
Why aren't 1Hz crystals used to measure seconds?
According to Wikipedia:
Many clocks use a 32.768KHz crystal. Is this because the crystal is smaller than a 1Hz crystal?
If 1.0 Hz == 1.0 second. Then, why the need for the division?
2
votes
4answers
105 views
What kind of oscillator should I use for a binary clock?
I've seen that a lot of clocks use a 32.768KHz crystal. I'm curious why that is exactly. I am working on a binary clock project with some 4520 ICs. I have some 555 timers too, but I want to use a ...
1
vote
5answers
189 views
Oscillator circuits operation?
Damped AC oscillations are produced in LC circuit by charging and discharging of capacitor and inductor but how it is achieved through an RC circuit as RC circuit is used in Colpitts Oscillator?
2
votes
1answer
85 views
Can I dynamically change the input clock frequency of the AT91SAM3X8E?
Background:
I'm attempting to use an AT91SAM3X8E microcontroller (for Arduino Due compatibility) to create a USB to \$I^{2}S\$ interface. Most \$I^{2}S\$ CODECs require a master clock that is ...
1
vote
2answers
149 views
180 Phase shift for oscillator
I am currently learning how to design/build a crystal radio receiver, transmitter and have a question for the 180 degrees phase shift for the carrier amplifier/oscillator system.
I commonly see this ...
2
votes
4answers
379 views
VCO for synth V/Octave and battery supply?
It's been a dream of mine to build an analogue synthesizer for a few years.
In this time I've built VCOs based on the 555 timer, which I know do not generally have an accurate frequency response ...
1
vote
2answers
173 views
Oscillation won't pass voltage buffer
This is the full schematic of the circuit
Full size: http://img443.imageshack.us/img443/9292/fulltheremin.png
It didn't work on the first try.
A theremin is an electric instrument which emit a ...
0
votes
2answers
86 views
Oscilating System
For a positive feedback system formed by an amplifier network A(s) and feedback network B(s), we have the following transfer function :
H(s) = A(s)/[1 - A(s)B(s)].
Quoting the Barkhaus Criterion, it ...
2
votes
0answers
150 views
Oscillating system via negative feed back?
The Barkhaus criterion for system with positive feedback (being \$B(s)\$ the feedback network transfer function and \$A(s)\$ the gain network transfer function) afirms that for a system to keep ...
1
vote
2answers
165 views
Overclocking an AVR microcontroller by using an external oscillator with higher frequency than uC supports
What would happen if I would connect an external oscillator that has a higher frequency than the microcontroller (AVR) supports? Will it blow up, constantly reset, or what?
3
votes
1answer
411 views
How to apply the Barkhausen criterion in order to know if a system will oscillate?
How to analyze or apply the Barkhausen criterion for oscillation of the astable multivibrator below?
The criterion talks about the magnitude of the products in a loop must be equal to 1 (ideally)
...
6
votes
2answers
330 views
Stability (phase margin) analysis in real feedback circuits
So I had a bright idea of using negative feedback to control offset current in my data acquisition circuit. Sure, you could do this in software, but removing the offset at the input stage would ...
1
vote
1answer
275 views
How to change the frequency of PIC internal oscillator?
Internal oscillator of PIC16f884 doesn't change frequency in the following code:
...
2
votes
1answer
248 views
Output of oscillator expected to be square wave, but looks sinusoidal
I've build a circuit exactly like the one below except Im using a SN74HC14N (schmitt triggered inverter).
The output of the circuit looks like this, however isnt it supposed to be more square wave ...
2
votes
1answer
611 views
Does the drive circuit for a piezo buzzer require extra power?
I want to power a small piezo buzzer with a battery, and I am trying to work out the power requirements.
The buzzer has a Rated Voltage of 3V, and the battery has a Nominal Voltage of 3V.
The buzzer ...
1
vote
1answer
544 views
How to configure PIC24H for 20MHz external oscillator?
The basic addition of a 20MHz external resonator is becoming much more painful that I thought. I've got a breadboard setup with a DIP package of a PIC24HJ128GP502. Nothing fancy, and it has been ...
2
votes
2answers
782 views
Using external oscillator for MSP430 Timer
I'm want to use an external low frequency crystal (32kHz) for the timer in my MSP430G2553 and the internal oscillator at 8MHz, but in the datasheet I can't see how I should use the external crystal ...
3
votes
1answer
102 views
PIC18 with ACT HC49/US XTAL
As part of my current project I need to ensure that my MCU (namely PIC18F4520) runs smoothly, minimizing the possibility of any interruptions. The datasheet ...
6
votes
2answers
428 views
Can a Hartley Oscillator be built using Fixed Inductors?
I've been playing around with fundamental circuits (no professional EE background), and became interested in oscillators. I have been trying to build the Hartley oscillator as described here. The ...
5
votes
1answer
368 views
Op amp analysis question
I was handed the following circuit in order to determine what it does and what is its operating conditions. The circuit was reverse engineered from an old equipment.
I have simulated with NI ...
2
votes
1answer
122 views
Will an oscillator be able to drive a transmission line
I want to build a soil moisture measurement probe based on this idea:
An oscillator feeds a transmission line burried in a soil via a termination resistor R1, XOR gate acts as a phase shift ...
2
votes
1answer
288 views
Incorrect frequency from crystal oscillator
I acquired an old Eistar SJ-1 Digital pulser. However the frequency it
generates is always 66% of what its supposed to produce. Turns out that
the frequency coming out of the frequency stage(at Pin ...
4
votes
1answer
325 views
Does Fosc refer to the crystal frequency before or after PLL is applied for PIC18 microcontrollers?
If I have a PIC18 microcontroller with an 8MHz crystal and 4xPLL, is Fosc 8MHz or 32MHz?
0
votes
2answers
126 views
Low Frequency, High Voltage Oscillator
I am trying to create a speed control for a brushless AC motor, like those used in fountain water pumps. Since the speed of the motor is determined by the line frequency I want to make a low ...
5
votes
1answer
271 views
How good is my xtal design on my pcb?
I'm designing a board for a school project using eagle. I thought I could get away with using the onboard clock of the PIC18 since it's not doing a whole lot (mostly just LEDs), but one of its tasks ...
