A device or circuit that generates an AC signal at a certain frequency.
-3
votes
0answers
27 views
Creating a variable wien bridge oscillator
I had been trying to build a variable wien bridge oscillator. The schematic is shown below. I want to change the frequency by using a pot, but it starts to distort after 12 kHz. Also when I am ...
1
vote
1answer
47 views
How the two Colpitts oscillators work?
I have just seen two Colpitts oscillators from the page as below.
However, the page is not written in English. I tried to translate it into English but I could not understand it.
Could anyone ...
0
votes
1answer
57 views
What is the most energy effecient type of RF oscillator?
Here are the options: the Gunn Diode, the Barkhausen-Kurz Tube(AKA "transmitting triode"), the so-called Lighthouse Tube, the cavity Magnetron, the reflex Klystron. I'm leaving out the Gyrotron ...
0
votes
1answer
61 views
Is it a bad idea to switch from using a quartz oscillator for my timing circuit to using a MEMS oscillator? [on hold]
I've read MEMS oscillators offer improved performance including phase jitter less than 500fs and frequency stability down to +-0.1ppm. It's difficult to switch from quartz because it simply works and ...
0
votes
1answer
40 views
I found what looks like a crystal oscillator with an xdl stamp I haven't seen before
I found an old transmitter with a crystal oscillator on it, when I looked at this I saw that it had "xdl 17.734475m" stamped onto it, I've only ever seen oscillators with just their frequency written ...
2
votes
1answer
87 views
250-350 MHz voltage controlled oscillator
I need to build a 250-350 MHz voltage controlled oscillator.
I have been checking out ring oscillators but they cannot reach these frequencies (max ~20 MHz).
Thus, I would like to know which are the ...
0
votes
1answer
77 views
How sine wave is generated in wien bridge oscillator? [closed]
It is known that the initial feedback signal is developed from the noise in the resitors and the transients of the power supply. The question here is : why the waveform at the output is sine wave ...
3
votes
1answer
61 views
Relaxation oscillator with two time constants
I have the following circuit and I have to find the duty cycle of the output signal and its frequency:
I figured out that if \$v_{cond} > 0\$, then D4 will be forward biased and D3 reverse ...
1
vote
2answers
355 views
What kind of oscillator is this circuit?(processor oscillator)
I was just seeing the datasheet of a motherboard and saw this oscillator circuit:
What kind of oscillator is this circuit? what are the usage of those resistors?
As you can see it has two input ...
0
votes
1answer
46 views
LC tank Q factor
I am working on parallel LC tank.
It is Rp // Lp // C .
Rp = Rs( 1 + Q^2 )
Since inductor dominates capacitor under high frequency, Rs is parasitic resistance of inductor.
It seems to me Q factor ...
2
votes
4answers
113 views
About using a crystal as notch filter
I am looking to create a high q passive notch filter using a crystal.
I am not very familiar with crystals, hoping that someone who's had a similar experience can enlighten. I know crystals are mostly ...
0
votes
0answers
55 views
Peculiar voltage spikes in triangular waveform generator circuit
I recently made a triangular waveform generator circuit using LM324 op amp. But the output of the generator had some sort of periodic spikes in it. However I was able to suppress the spikes by ...
0
votes
1answer
42 views
ATmega328 external crystal capacitor requirements
I am reading this guide and it states that, in order to use an external 16 MHz crystal for an ATmega328, I need two 22 pF capacitors.
I found this bundle of two 20 pF capacitors and the crystal (sold ...
-2
votes
1answer
15 views
Voltage input values for Si550 voltage controlled oscillator?
I am trying to find the required voltage input for a particular Mhz frequency output, I chose a voltage controlled oscillator to allow for user over/under clocking.
Datasheet, I probably missed ...
1
vote
0answers
77 views
voltage controlled oscillator
Given below is a VCO circuit. Can anyone explain how the components work (especially the resistors and capacitors) and why the resistor and capacitor values are selected so. and what are the values to ...
-2
votes
1answer
77 views
Design of audio playback system
I'm having trouble understanding some concepts:
In a complete audio playback system the out put of the DAC is connected directly to the input of the low-pass filter, and the output of the low-pass ...
1
vote
1answer
49 views
Strange behavior on transformer driver
I'm trying to make a circuit to drive a transformer from a PWM signal produced by an AVR MCU. Here's the schematic:
The MCU output in fact has 2 complimentary PWMs feeding two transistor pairs. For ...
0
votes
0answers
29 views
How LTC3108-1's oscillator work?
I am reading about LTC3108-1 on the page.
There is one part about oscillator that I am not sure how it works.
Could anyone explain it more detail? Or could you give me a link so I can read up?
...
0
votes
0answers
26 views
RC Relaxation Oscillator Problems
I found a schematic for this oscillator online here and I tried it, but instead of the LED turning on and off sawtooth style, it got brighter slowly, and stayed bright without getting dimmer. What is ...
0
votes
0answers
45 views
Can anyone please explain the working of a radio transmitter
I found this circuit online:
I found explanation on how a radio transmitter works in this site:
http://www.dummies.com/how-to/content/radio-electronics-transmitters-and-receivers.html
However, I am ...
0
votes
1answer
76 views
Wien Bridge Oscillator with LM358
I am constructing 10kHz , 30kHz and 50kHz sine waves using wien bridge oscillator design with LM358 OP-Amp. I have a few problems with the circuits that i could not figure out. Thank you for all your ...
5
votes
2answers
765 views
How does this oscillator work under a constant DC voltage?
Consider:
How does the oscillator in this circuit work? A tank circuit can't oscillate when there is a constant DC voltage, am I wrong? I simulated the circuit in NI Multisim and couldn't observe ...
3
votes
2answers
55 views
FCC Specialized Oscillator - for low frequency exemption
According to the FCC:
The following devices are subject only to the general conditions of operation in §§15.5 [Dealing with certification] and 15.29 [Dealing with power] and are exempt from the ...
-9
votes
2answers
89 views
Transistor Use In Oscillator Design [closed]
Need to know how to actually make the transistor 2N3055 turn on and off at a set frequency to implement its use as an Oscillator. that is the Main event that I do not know.
Given this information then ...
4
votes
1answer
77 views
Clock Oscillator - Topology and PCB Layout recommendations
I'm designing one of my first layouts and I've read a lot of articles and StackExchange questions about guidelines and recommendations.
It's a university project realized by another student that I ...
0
votes
1answer
36 views
colpitts oscillator with jFET not working
I decided to build a colpitts oscillator using a jFET (2N3819):
It seems to work fine @ http://www.falstad.com/circuit/ but when i try to build this circuit it does not work, any ideas?
Thank you ...
1
vote
1answer
45 views
Effect on opamp lead length for non-functional wien bridge oscillator
I've built two diode stabilised variable frequency wien bridge oscillator circuits according to this schematic:
(source). Both are on the same stripboard and connect to a single LM324.
One of the ...
0
votes
0answers
27 views
How do I design an antenna in desired frequency with preset equivalent circuit model?
I am working on a project that an oscillator drives 1 mH inductor in 7.5 KHz. This oscillator also happens to be very efficient. However, I am constrained with inductor value. So, to make my design ...
1
vote
3answers
102 views
Why doesn't this transistor circuit work as expected?
This is a circuit I have designed to work as an oscillator. But it doesn't work.
The way I supposed this works:
When power is ON, the capacitor(C1) starts charging through 1Kohm resistor. Once it ...
4
votes
1answer
348 views
RC oscillator ageing
I know that a crystal oscillator has a particular ageing curve, that shall be taken into account when designing a long-term application.
But what about the RC internal to the MCUs? I did not find ...
1
vote
2answers
57 views
Sawtooth VCO and current source for modular synthesizer
I have been working on a current source and sawtooth core VCO based on the Electronotes/Aaron Lanterman/Ian Fritz designs/ideas.
I have breadboarded out the attached VCO schematic; the transistors ...
1
vote
2answers
82 views
resonator or Crystal Oscillator for atmega2560
I've received the PCB that I have designed.
This PCB has an atmega2560 on it.
I have designed it to use a Crystal Oscillator such as this figure shows :
Is this designed supposed to work on an ...
0
votes
1answer
88 views
How to find the resonant frequency of a human body?
I've read that the human body has resonant frequencies somewhere around 50MHz. I also think it would be interesting to look for values in other ranges like 10-100 kHz. I'm wondering how to build a ...
0
votes
2answers
59 views
How to balance between frequency and duty cycle in this circuit?
I have this astable circuit that generate square waves with independent control of frequency and duty cycle:
For this circuit:
$$t_H=0.759\,C\,(R_f+R_y)$$
$$t_L=0.759\,C\,R_x$$
$$period = 0.759\,...
7
votes
3answers
185 views
How to improve the full bridge / half bridge start up time?
I am trying to find out a way to improve the rise /start up time of a series LC circuit placed in a full bridge (or half bridge) circuit.
Here is a simplified schematic. The circuit works very well, ...
4
votes
1answer
51 views
LC Oscillator Gain Compression
I am designing an LC Colpits common base Oscillator for the FM broadcast band. The project is going to be extremely low radiated power as I will only be using it in my car.
I am currently using this ...
0
votes
2answers
70 views
Output impedance of an oscillator
I'm using a 27MHz oscillator and trying to measure its voltage level and waveform with oscilloscope. But I have no idea how to match the impedance of oscillator and oscilloscope, since the data sheet ...
1
vote
1answer
69 views
Unwanted oscillations and distortions in buck converter
I've tried today to design a very simple and crude 26V to ~12V buck converter. But after testing it in LTspice I've got some weird and unexplained oscillations and distortions. The oscillations ...
0
votes
0answers
40 views
Initial voltage of a oscillator
I'm currently trying to test the initial voltage of the oscillator below. The test circuit in the datasheet only gives me Rt (2.7k) and Ct (.01uF) which I have to gnd and 20v to vin. I'm not getting ...
0
votes
1answer
74 views
Wien bridge oscillator circuit doesn't work
I've connected the circuit of Fig 3.4.6 in this link which is shown below:
Here is the circuit that I've connected:
Where in my circuit:
R3 = 100 kOhm
R4 = 47 kOhm
R1 = R2 = 5.1 kOhm
C1 = C2 =...
1
vote
3answers
91 views
What can cause an oscillator output voltage to go higher than expected?
I am currently testing a 50MHz 3.3V CMOS oscillator in my circuit, which is connected to two pins/loads - MCU pin and Ethernet PHY pin. The oscillator is rated for 15pF output load, which I could be ...
0
votes
1answer
65 views
Minimum voltage for a RC Oscillator
I am trying to run an RC oscillator using a 2n3904 the circuit looks like the following.
You can see the live circuit here. Simulation I want to run it at 0-5v but I am not getting the result, I ...
0
votes
0answers
36 views
Error in 'Multisim' when connecting two op amps in cascade
I've connected the circuit below (wien bridge oscillator) and simulated it using Multisim:
The results were expected: a sinusoidal wave of 1.2 Vp-p.
I wanted to amplify this resulting signal, so I ...
0
votes
1answer
62 views
How can I build a dual potentiometer?
I am about to build a wien bridge oscillator circuit which is shown in the figure below:
However, I need a dual potentiometer to do so, because the resistors VR1a and VR1b must have the same value ...
1
vote
2answers
34 views
Best circuit to get an array of signals with the same frequency and edge-synchronizable to a reference but individually controllable duty-cycles?
I am looking to build a circuit to control five different FET drivers individually. The input signal would be a single shot from a function generator, which should produce five output signals, with ...
0
votes
2answers
72 views
Application of LC circuit(tank circuit)
I have read that tank circuit is used for radio tuning. When we tune a radio we change the variable capacitor, hence the value of LC changes. This would result in a change in the resonance frequency. ...
0
votes
1answer
115 views
How to drive power MOSFET at 1 MHz
As part of a radio transmitter design, a square wave oscillator has to drive a power mosfet. Given the gate capacitance and the frequency, the maximum current should be around 50mA.
The power mosfet ...
1
vote
1answer
72 views
555 VCO Circuit - Speaker to VCC?
Hello!
I have a simple question concerning this circuit I have built:
It is a 555 Voltage Controlled Oscillator I have built as a foundation for my signal generator circuit. The circuit works great,...
0
votes
1answer
49 views
Can I use a Quarz Oszilator instead of a Standard quartz?
I want to complete this tutorial on burning a bootloader onto a atmega328. There a Standard quartz is used, but called a Quarz oszilator. Now I bought this Oszilator. Can I use the oszilator as well ...
0
votes
2answers
75 views
Need approval of transformer driver design
I designed a circuit from several ideas I saw before and I'm a bit too impatient to build the thing myself.
(http://imgur.com/KD97NuJ)
Basically, it's a two-transistor oscillator combined with an ...
