Questions tagged [oscillator]

A device or circuit that generates an AC signal at a certain frequency.

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4answers
2k views

Why does this transistor oscillator not work at 100 MHz?

I tried to simulate this oscillator in Multisim, but it doesn't work, I get just DC voltage from it. With the same biasing I got to make it work, but on lower frequency (around 1 MHz), while I want to ...
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2answers
75 views

Does DC voltage affect the frequency?

Does DC voltage supplied to the tank circuit impact its frequency? Imagine that varactor is just a normal fixed capacitor, but for some reason there's voltage supplied between the capacitors. Ignore ...
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0answers
28 views

Apsk modulation in lt spice

Greetings according to the schedule, help to do APSK modulation in LTspice. I built oscillators and the ideal AM modulator but whow make variations for amplitude and phase become 16-apsk is my biggest ...
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3answers
668 views

How does this oscillator work in radio transmitter?

I have a hard time understanding how the oscillator works in this circuit. The oscillator uses varicap diodes V1 to change the frequency of oscillation. But this circuit is very different from a ...
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3answers
103 views

Do 1MHz 3.3V through-hole oscillators exist?

I'm beginning my first MCU project and I'm having trouble finding a suitable oscillator. I want to run an ATtiny261 at very low power. It will be lighting up different combinations of LEDs based on ...
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3answers
285 views

Can you offset the phase of a crystal oscillator so one XO is 180 degrees out of phase from the other?

I need an ultra low jitter/phase noise 100Mhz crystal oscillator with phase noise of less than 70dbc @ 1 hz and less than 100dBc @ 10Hz and the lowest jitter I can manage and I need a differential ...
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1answer
73 views

Using an oscilloscope to measure the gain of an op-amp circuit (with capacitors)

I have an upcoming laboratory exam where we have to construct an op-amp circuit (from our experiments the circuits were always varied and probably will be a bit more difficult on our exam.) We are ...
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1answer
70 views

Is this radio receiver/transmitter plausible?

Previously I have created a simple radio receiver using the schematic below (based off a crystal radio), and I was wondering if the modified circuit which is also below would work for a simple morse-...
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1answer
93 views

Why does the blue pill STM32 use two oscillators?

I'm designing a PCB and I was looking at the schematic of the blue pill STM32 board to integrate it, and found that there are two crystals on the schematic? Why is this? Also, there is only one on the ...
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4answers
176 views

Positive feedback in Op-Amp Oscillators

Is positive feedback necessary in op-amp oscillators? Can you make one using negative feedback?
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3answers
54 views

Phase noise and RMS jitter scaling with frequency

The phase noise plot for a particular crystal oscillator is here. The datasheet represents an entire series of oscillators which range in frequency from 1 to 75MHz. The phase noise plot is indicated ...
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1answer
67 views

Notion of Q factor for abstract Two-Port Network

Consider an abstract two-port network/quadripole electrical network with input voltage \$U_{in}\$, output voltage \$U_{out}\$, current at input port \$I_{1}\$ and current at output port \$I_{2}\$: ...
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1answer
53 views

How to identify this SMD crystal oscillator or resonator?

I need your help to identify this SMD crystal to fix a car ECU. It is marked AR and has 3 pins on the bottom. How can I find the frequency or specifications to order a new one or test this?
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60 views

ZVS-driver not properly inducing heat

First of all, please forgive me some spelling mistakes, my english isn't the best. Feel free to tell me if I forgot to mention any important information. A few days ago, I built a ZVS-driver circuit, ...
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3answers
91 views

Why does the astable multivibrator using transistor not work when I use the same value of resistance for the collector of both the transistors?

The circuit shown in the figure does not run even in proteus. But when I change the collector resistance above 1.43k of one of the transistor, the circuit starts working. What's the reason behind such ...
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0answers
55 views

How to calculate RC values according to threshold points of a Schmitt trigger inverting oscillator [updated]

I'm trying to make a high-period, low duty cycle signal to trigger a regulator (EN pin) for lower power consumption. I tried to simulate this simple circuit in various simulation software, using "...
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2answers
117 views

What can negatively impact a motherboard's / CPU's clock generator / oscillator?

Is it possible for a clock generator / oscillator to be skewed by something from the electrical grid (e.g. to work perfectly fine at place A, and have issues at place B - all reproducible)? What would ...
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0answers
100 views

How does a driving voltage affect an LC circuit?

I need help understanding how the drive voltage \$V_d\$ and the coupling capacitor \$C_d\$ in the circuit above affect the total energy of the LC circuit. The author arrives at the following equation ...
3
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1answer
119 views

Analog synthesizer- Add second VCO

I am working on reviving an old synth design (Transcendent 2000), but I would like to add a second oscillator. I was thinking of doubling the circuit highlighted below, and sharing the pitch control (...
3
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2answers
210 views

How can this circuit oscillate at a VHF frequency?

I am practicing RF. I have looked at an FM transmitter circuit in a video. I went on to analyse it. When the analysis got to the tank resonant circuit, I could not get it. This parallel LC circuit is ...
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1answer
60 views

What crystal oscillator for a CH340G? [closed]

I think this should be a relatively simple question. I need to know what would be the best kind of 12Mhz crystal to run with a CH340G driver. I know barely anything about oscillators, and everything I ...
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1answer
90 views

Slayer exciter doesn't work

I know that similar questions have been asked here, but none of the answers seem to work for me. Also, I am new to this site, and I am not much of an expert when it comes to electronics, so feel free ...
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3answers
56 views

CMOS active crystal oscillator output voltage uncertainty

I want to use SG7050CAN CMOS active crystal oscillator as reference input to ADF4106 PLL. The input voltage level is 0.8/AVDD Vp-p min/max. Now, the SG7050CAN datasheet says, it's low voltage is 0.4 V ...
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2answers
48 views

CMOS active crystal oscillator load capacitance, to be used for PLL reference

I do not have a clear idea of what load capacitance is. I am looking forward to use the ADF4106 PLL with a ~580 MHz VCO to synthesize the frequency. For the reference input to the PLL, I wanted to ...
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0answers
38 views

Multiple Crystal Oscillators Design Considerations

I am designing an acquisition system that has two parts, a hub and an acquisition part that collects the signals. The two parts communicate through FPGA Serdes. The hub has a main clock from 16MHz ...
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1answer
68 views

Op-amp Colpitts oscillator

I have a question about op-amp Colpitts oscillators. I am a hobbyist building a sine wave oscillator circuit for an experiment. The frequency of the output is one of the variables in the experiment ...
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1answer
70 views

Switching the direction of DC current flow to a load

I am a beginner (Software field) trying to do some basics in electronics. I have got a load and a power source like this My requirement is just to switch direction of dc current to the load in a ...
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3answers
151 views

Can a practical steady-state electronic oscillator be a linear circuit?

Can a practical steady-state electronic oscillator, made of an amplifier (an OA) and a feedback loop be a linear circuit? Apparently, this is not possible as long as a linear oscillator can never ...
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2answers
120 views

PNP Astable Multivibrator Variation

I am trying to learn astable multivibrator circuits and I found one in an EL wire driver. I have noticed it has a 100nF ceramic capacitor connected between the transistor bases and additional 22R ...
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2answers
98 views

Trouble With Transistor (BC547) in Oscillator Circuit

I am brand new to building circuits, so I apologize if I use the incorrect terminology. I am trying to build an oscillator circuit that will output a Triangle Wave and Square Wave in tandem (trying to ...
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3answers
110 views

Understanding Colpitts "control" elements

I'm struggling to build a Colpitts oscillator that runs above about 2 MHz. Unfortunately, my understanding of this thing's theory of operation is severely minimal. My end goal is to build a crystal ...
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1answer
57 views

Correct wiring of crystal oscillator with MCU?

Actually this is a basic question I can't answer myself to be honest. I am using a MCU which requires a HSE: Now, this is for a crystal, but how do I connect a crystal oscillator with the MCU? The ...
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4answers
94 views

Making a simple 555 sawtooth VCO stable?

I have figured out how to make a sawtooth VCO using a 555 IC , by using a current mirror. The issues I am having is I can't make it stable at all. Its having random issues like it randomly changes ...
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1answer
69 views

sniffing a 32.768kHz low-power oscillator

I'm troubleshooting a real-time clock and suspect that under certain conditions the oscillator stops. How could I check if it is running, especially when the RTC chip is on battery power? It is Maxim ...
2
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1answer
58 views

3-stage Differential Ring Oscillator simulation output remains at DC Value

I'm currently simulating a 3-stage differential Ring Oscillator in LTSpice. I have setup one of my differential stages and created a symbol for it to use in the ring oscillator. I have double checked ...
4
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2answers
111 views

Why is it suggested to power XOs with LDOs?

I've read in various places that crystal oscillator ICs require very clean power (as opposed e.g. to your usual 3.3V rail from some switching regulator) and one way to achieve that was via LDOs. (Ref1)...
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1answer
105 views

How to choose correct resistor values for Colpitts Oscillator

I am having a hard time understanding how to pick resistor values to get the circuit to run. I think I have the basic design down correctly but feel like my resistor values are wrong. I calculated \$...
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2answers
49 views

Oscillator frequency in WS2811 chip

I have some RGB LEDs that are driven by the popular WS2811 chip made by World Semi. Datasheet is here. I find the following to be true: The datasheet says that the chip includes an oscillator running ...
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3answers
2k views

Do crystal oscillators synchronize by themselves when coupled by supply voltage?

I watched an excellent video about The Surprising Secret of Synchronization There are examples of pendulum clocks or metronomes synchronizing when coupled by a swinging platform. Other examples are ...
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2answers
109 views

4 Pin Cyrstal Oscillator Pinout to connect to Xi and Xo of CH340G

I need to connect a crystal oscillator to CH340G USB TTL converter, the oscillator I have is 3N12000G33YC with pinout and test circuit shown. It has 4 pins which I am unfamiliar with, I only know ...
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2answers
53 views

Synchronization of remote sensors

I have a project that involves multiple (5+) remote sensor units (custom PCB with a MCU, WiFi Radio, and sensor), that record data for a short test (<60 seconds). Each sensor records data ...
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1answer
108 views

Common Collector Colpitts Oscillator - Feedback analysis

I am a student working on a project where we are using CC Colpitts oscillators as local oscillators. We've chosen the above values based on the condition gm > w02C1C2RL,series, which for the given ...
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0answers
21 views

Setting the frequency of PWM controller KA7553

I am designing an SMPS (single switch high-PFC flyback in voltage mode inspired by an article) around the voltage-mode IC KA7553. However the datasheet for this part is really short and skimps on some ...
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2answers
63 views

Square wave frequency upsample with crystal oscillator

I'm trying to accomplish the following without the use of a microcontroller: Input: A square wave with a 1 Hz period, duty-cycle of 100 ms (10%), normally low. Output: A square wave with a 100 Hz ...
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1answer
42 views

Schmitt Trigger CD40106 has 5V at input with nothing connected

I am using Schmitt Trigger CD40106BE to make an PWM oscillator with controllable duty cycles. The schematic is shown below: However, the LED that should be blinking is constantly on. After some ...
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1answer
86 views

Why is Vout less than Vcc here in a way disproportionate to beta? [closed]

Given: Vcc=9V, duty cycle = 0.5, oscillation frequency=500Hz Note that I am not interested in electronics in any way (I'm planning to continue as a web developer yet need to finish my CCE major) so I ...
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0answers
47 views

Help picking a transistor for and analysing a colpitts oscillator

I am working on a development board for a digital synthesizer. I have set up a colpitts oscillator circuit for the oscillator that is needed by the microprocessor. I picked originally a PMBS3904 as ...
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2answers
117 views

Why isn't this multivibrator working?

I've built a simple multivibrator circuit and PCB but I get no oscillation whatsoever. I am expecting an oscillation on pin 3 of each transistor but get 0V on TR2 and 12V on TR1. Can anyone suggest ...
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1answer
166 views

How to avoid decay in quadrature oscillator?

Let's consider following quadrature oscillator below (source). It should provide two 90° out of phase sine signals with equal amplitude. It consists of two inverting integrators as well as an ...
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0answers
116 views

Why are 30 MHz crystal oscillators commonly used with FPGAs?

I am new to FPGAs. I am working on a clone board that has a Spartan 3AN. There is a 30 MHz crystal oscillator on board. I have checked another boards and noticed that 30 MHz is commmonly used. Is ...

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