A device or circuit that generates an AC signal at a certain frequency.
18
votes
4answers
2k views
Why does a faster clock require more power?
If you overclock a microcontroller, it gets hot.
If you overclock a microcontroller, it needs more voltage.
In some abstract way it makes sense: it is doing more computation, so it needs more energy ...
9
votes
4answers
457 views
Low power, low voltage, slow (0.1Hz) oscillator?
I had the opportunity to analyze a very interesting circuit today using a programmable unijunction transistor as a timer.
The power supply varies, and the circuit must operate on under 10uA of ...
9
votes
3answers
1k views
Crystals, Oscillators, and Resonators. What the difference?
I am trying to figure out the difference between crystals, oscillators, and resonators. I'm starting to grasp it but I still have some questions.
From my understanding, an oscillator is built from a ...
8
votes
8answers
3k views
What's the easiest/cheapest variable-frequency sine wave oscillator?
A Google search will give you a few billion ideas. Which is the simplest/easiest/cheapest that you know of?
Generating a square wave and then filtering out the harmonics isn't a good solution unless ...
7
votes
1answer
666 views
My 12 MHz crystal does not oscillate
I am having trouble with a board I have had fabricated. The processor is an NXP LPC1788 Cortex-M3.
I am using a 12 MHz external crystal to clock the processor as recommended in the datasheet.
...
7
votes
2answers
155 views
Can vibrations of quite an appreciable amplitude affect the clock signal of a crystal oscillator?
I'm very curious to know as I was told that these crystals are electro-mechanical transducers. So theoretically any excess mechanical vibration should result in an error, right?
7
votes
2answers
313 views
Oscillator Driven LED - Not Oscillating
I have an IR LED which is switched at a rate of 32.768kHz from an oscillator circuit (relevant portion shown below). I have 10 prototype PCBs. 30% of them work while the others don't. The problem is ...
6
votes
2answers
633 views
Sharing an oscillator between two ICs
I have a microcontroller and an FPGA on the same board. If they're both going to run at the same clock speed, can I just use one oscillator to clock them both? There seems like there is something I ...
6
votes
3answers
238 views
Grokking oscillators
Can someone explain to me / point me to a good explanation of the theory behind an electronic oscillator? The Wikipedia entry explains what, but not how, which is what I need to know.
TIA.
6
votes
2answers
347 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 ...
6
votes
3answers
1k views
How do I use a quartz crystal in an oscillator?
How can I get a quartz crystal to make square waves at 4.096MHz? So far I have the 4.096MHz quartz crystal and this schematic I saw:
Where can you find an amplifier with a single input and what ...
6
votes
2answers
278 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 ...
6
votes
2answers
352 views
Role of capacitor in this circuit
I have troubles understanding the role of C1 capacitor in the oscillating circuit from the schematic below:
My question is: what is the role of C1 in this circuit?
Is it to ensure that the circuit ...
5
votes
1answer
315 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 ...
5
votes
3answers
1k views
High-stability oscillators (non-crystal)
Are there any high-stability oscilators, which are not crystal based, given that temperature is stable down to 0.01 C and voltage down to 0.001V?
Will LC-based oscillator be able to show performance ...
5
votes
4answers
365 views
What causes oscillators to sync up with each other?
Messing around with simple Theremin circuits, the variable oscillator would get "stuck" in sync with the reference oscillator, and not move until disturbed significantly (like "snap to grid" in a ...
5
votes
4answers
905 views
Push Pull Oscillator
Does anyone know how to build a push/pull oscillator or a similar square wave oscillator?
5
votes
3answers
254 views
Vacuum tube LED flasher
I am wondering if I can make a vacuum tube oscillator for a LED flasher.
The problem is I only have 4 vacuum tubes: 14GT8, 12AU6 and 2 12BA6 tubes. I have a 12 volt DC power supply, 10 volt AC, 20 ...
5
votes
1answer
230 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 ...
5
votes
1answer
300 views
How can I invert a solar-powered oscillator's frequency?
I have a hobby project that's been on the backburner for about 3 years now. It's very simple - just a solar-powered oscillator hooked up to a speaker, that changes frequency in response to the level ...
4
votes
4answers
2k views
Internal or external oscillator
I always use the internal oscillator that pics have as I have never found the need to run anything at higher frequency than 8 MHz (which is the fastest the pics I use tend to be able to go). Are there ...
4
votes
5answers
1k views
What is the simplest way to make an oscillating signal?
Imagine you have a black box with 5VDC and ground inputs and you have to create one output that is an oscillating signal. What is the simplest circuit that can do so? Can you create a tank circuit ...
4
votes
4answers
327 views
3 phase computer chip
I have just had a conversation with a friend who studied quantum computing. Sadly I have forgotten most of the conversation as it was far beyond my knowledge threshold.
Essentially he was saying was ...
4
votes
6answers
1k views
PIC keeps resetting: Am I seeing side-effects from breadboard use?
I'm using PIC18F4680 and am having problems running it form a 40 MHz external clock source or 10 MHz crystal in HSPLL mode. Using 10 MHz crystal in HS mode seems to be fine and 5 MHz crystal in HSPLL ...
4
votes
4answers
322 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?
4
votes
6answers
465 views
Design for an analogue oscillator that doesn't drift in frequency?
VCOs (Voltage Controlled Oscillators) in analogue music synthesizers are notorious for drifting with temperature. What design solutions are there for an analogue audio VCO that keeps close (as in ...
4
votes
2answers
312 views
Clock Shape Changes with Two O-Scope Probes
I have a Max V CPLD development board which has a 10MHz oscillator onboard. I hooked up CH2 probe to the output pin and then wrote a small VHDL program that output the clock to an external pin. I ...
4
votes
1answer
4k views
How to design the capacitors used with Crystal Oscillators?
I have seen circuits involving crystal oscillators connecting two capacitors between each of the crystal legs and ground. I would like to know how to design the value of these capacitors for different ...
4
votes
2answers
268 views
Building an oscillator out of discrete gates
I want to buid an ocsillator out of discrete XOR gates, I want to acheive 80MHz.
I've tried building one from SN74LVC2G86, but rise/fall times I get is about 25ns. Datasheet does not specify the ...
4
votes
1answer
224 views
Setting the internal oscillator speed on PIC12F1822
I'm trying to get a PIC12F1822 to run at 32 MHz. Here are the relevant bits of code:
...
4
votes
2answers
1k views
Problem with a Relaxation Oscillator (using Op Amp)
I'm studying a relaxation oscillator. This wikipedia circuit shows exactly my circuit with the only difference that I'm using different values for each resistor.
I called resistor R the one ...
4
votes
2answers
312 views
PIC24 Internal Oscillator and Instruction cycles
I have some relative experience on AVR but just minimum with PICs. In order to start a project I've just wanted to verify that I was able to get the internal oscillator working at the right ...
4
votes
1answer
141 views
Does a clock oscillator require a load?
I want to use this clock oscillator
http://www.ecsxtal.com/store/pdf/ecs-2100x.pdf
It does not require loading capacitance.
However, it says "3.3V operation (optional)", yet on the same page it ...
3
votes
5answers
1k views
Is this a suitable sine wave osc? how would I control the frequency?
Overview-
I'm making a bank of analog sine wave oscillators and I'm interested in keeping the design compact.
I've started by making a Wien Bridge oscillator. As I'm working from a single power ...
3
votes
3answers
181 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 ...
3
votes
3answers
183 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 ...
3
votes
4answers
459 views
Why is this oscillator unstable?
I designed a simple triangle wave oscillator based around a switchable curent soure. It works for a few cycles, then it becomes unstable and finally stops working altogether. Why is this?
If anyone ...
3
votes
2answers
148 views
How to connect 4MHZ crystal oscillator to get 16MHZ
I've a 10 pieces of 4 MHZ crystal oscillator.
I need 16MHZ crystal oscillator. Can i connect somehow (serial, paralel) more 4MHZ oscillators, and get 16MHZ?
3
votes
3answers
456 views
Stabilizing opamps - am i doing it right?
I'm designing a high current linear regulator and learning about real opamps as opposed to ideal ones described in tutorials all over the net as i go.
My initial voltage regulation design was ...
3
votes
2answers
283 views
Are there any commercially available crystals in the sub 32 kHz range?
I'm looking for a low power clocking solution and it looks like crystals bottom out at 32 kHz. Are there any low power (nA) solutions (crystals/ceramic resonators/custom transistor oscillator ...
3
votes
1answer
665 views
Negative Charge Pump with Ring Oscillator
I was told it was possible to get a negative voltage from a ring oscillator (that doesnt go negative), I was wondering how is that possible?
Thank you in advance.
3
votes
3answers
514 views
Novice question about low-pass filter
I am trying to construct a simple low-pass filter for the following scenario: A high-voltage DC signal with lots of noise. I looked at Wikipedia's article on a simple passive low-pass filter. I ...
3
votes
1answer
164 views
Is using a shorter timer period less accurate than using a longer one?
I'm using a dsPIC 33FJ128GP804 and I'm trying to record data at 200 Hz as accurately as possible. My device also has a GPS and I'm noticing that my timer is drifting compared to the GPS by about 333 ...
3
votes
4answers
2k views
Using the ATMega328 with the internal oscillator?
I have a project that I think would be best suited for an ATMega328P. However, in every simple project I've seen, people always hook up a 16MHz external oscillator. From what I can see, it should have ...
3
votes
7answers
1k views
Using microcontroller as oscillator for high voltage power suppy?
MightyOhm has designed a geiger counter which is here. I am not very clear but I think he is using the 555 timer as an oscillator in the high voltage power supply section. I've attached his schematic ...
3
votes
2answers
134 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 ...
3
votes
1answer
181 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?
3
votes
1answer
110 views
Possible to tap a PLL signal as a clock for multiple devices
We have an oscillator providing a clock signal for an MCU. It has oscillator in and out pins: XTAL-IN and XTAL-OUT.
We'd like to use the same clock signal as a digital clock input to another MCU. ...
3
votes
1answer
147 views
Binary Counter and an Oscillator for frequency generation
I'm interested in creating low frequencies using a high-frequency oscillator. For example - using a 12Mhz oscillator to create 1Khz, 2Khz waves.
I've been said that using a Binary adder(oops) counter ...
3
votes
1answer
86 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 ...
