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264 Threads found on edaboard.com: Oscillator Transistor
Ring oscillators aren't going to be naturally frequency- linear in any case, and less so as you slide across the low end where current is exponential w/ VIN (worse than square-law at the big end). You probably need to make the bias scheme more elaborate, with current being the function of control voltage which makes the linear-frequency result (may
Why don't you get a 150Mhz crystal and create a transistor oscillator. Than it will be Sine wave.
You oscillator is pulled by simple transistor mixer and its frequency/amplitude is shifted by modulating signal.Any matching circuit is not necessary @ 1MHz but you should evaluate your circuit with elegant circuits such as double balanced mixer.Or you can isolate your oscillator by adding an extra buffer circuit.Meanwhile, your (...)
Almost all superhet receivers use single transistor oscillator/mixer stages to produce IF ready for filtering and amplification so just about every radio you have seen uses that principle! The design in your diagram appears to be just a modulated oscillator, I'm guessing to run at around 800 - 1000 MHz. As it has no reasonable output point (...)
I understand it's just an oscillator without power amplifier on output. It's actually two oscillators, T1 is generating the 5.5 MHz audio subcarrier. BF244 can probably work with circuit modifications, but why not use a 1 - 5 GHz fT small signal RF transistor?
Hi I want to design crystal oscillator (pierce) but i have in trouble... Proposed oscillation frequency is around 39MHz And i used crystal L~4mH C~4.1fF R~10ohm Co~2pF C1 C2=20pF(shunt cap for drain to gnd& gate to gnd) Feedback resistor ~ 1Mohm Vdd~1.5V transistor gm~80u However, my oscillator input/output settles to same (...)
cross coupled of two transistor will give negaive impedance therefore negative gm, or transconductance. it will compensate for loss of inductor and resistor therefore commonly used in oscillator design. now why the same configuration used in a latch or storage element? so, you want the same type of oscillation happen in a latch?
You are trying to use a Harley oscillator as a transmitter? You need to design the transmitter from the grounds up and measure the values and select the operating point of the transistor carefully.
Brief explanation of the phase shift oscillator operation principle in this Wikipedia article
It will be both educative and entertainment to design a transistor oscillator with a hand made low power transformer - the voltage can be high but the current can be low (must be very low) and you will not get a shock. Transformers (most of them) do not have cancer causing parts/ elements and they can be very small because they will not be handling
I am following RF design book and tutorials on negative resistance oscillator, but encounter some problems. My design is 5GHz oscillator. I want to use single device, so i decided to use NE3210S01, it has very high gain, there are many papers with push-push, etc. oscillators, where NE3210S01 fundamental oscillation is at 3...9 GHz. My (...)
You do not have a piezo buzzer. Instead you have a piezo transducer (a piezo speaker). A piezo buzzer has a built-in transistor oscillator to make it beeeeep when a DC voltage powers it. A piezo transducer is attached to a metal plate and it expands which causes the assembly to bend in one direction when voltage is applied and it bends in the other
The turns ratio depends on the output impedance of the transistor. The Vb is 4.7/14.7 X 12 ~ 4V so Ve ~ 3.3 so the Ic is 10mA. This is the standing bias on the transistor. During the oscillation cycle it is impossible for the current to go down to zero , so the negative peak RF current is say 9mA. I would presume that the positive half cycle w
You do not have an oscillator because there is no transistor or opamp to keep it going. Instead you have an LC that rings like a tapped bell. The pulse activates it with power causing it to ring for a moment if the power is applied through a series resistor, then it rings again for a moment when the power is disconnected. It can feed an amplifier
Hello everyone! I wish to design a ring oscillator of 250 Hz (without using inductors and capacitors ) with two differential outputs. But the phase difference between the two outputs should be exactly 180 degrees. Also I need the output DC to be 900mV. I am using 1.8V supply voltage. Can anyone suggest me some paper for the same??
Apart from reasonability of this application, you need a resonant oscillator circuit to suppress possible fundamental wave oscillations.
Sounds like you have build a nice oscillator with the segment or digit driver transistors. Long PCB traces are a prerequisite to make it oscillating. There's a problem in your circuit, not directly related to the "ringing" problem which should be fixed first. The npn transistor segment drivers are only partly turned on by the 3.3V base (...)
Hi I want to experiment with this simple oscillator that uses a BF245A transistor. It uses the internal capacitances of the fet to minimize component count. 1. Can I use J310, because I do not have a BF245A? 2. Are there any other types of more powerful transistors I can use, so as to convert it to a more powerful (...)
As this component is part of an oscillator/driver (frequency not given). Its either a part or is the Vcc stabiliser circuit. Or if the driver is producing 10W of MF, it could be the actual RF output device. As you have removed the device, power the unit up and check on the connections which went to the device. If you find 10V of RF on one, it g
Normally you want the buffer to draw only minimal power from the oscillator. The aim is to avoid loading the oscillator.
Totally agree. The rule of thumb designing ANY oscillator is to have minimum power possible. This would help for all of the oscillator characteristics, as frequency stability, phase noise, harmonics, etc. After that, you can amplify the oscillator signal however you want and get any power you need.
Yes, something like this. Consider that the transistor power disspation may be different without oscillations, the bias circuit may need to be switched, too. Hi, how can I get more power out of this oscillator? The greater power so far is 4W at 22v with a 2sc2166. I have also tried the much more powerful 2sc3133
hi, i am trying to simulate colpitt oscillator in Proteus. the circuit is supposed to work for 100MHz. following is the schematic diagram. it is not working, i see only decreasing oscillating signal at the output. 121032 121033 i also doubt the value of C1 and C6 capacitor values, how are
i am trying to simulate oscillator design using transistor BFR360f for these non linear simulations , i am using large signal and small signal s parameters of BFR360f however when i do the simulation using "harmonic balance" simulator, i get an error saying require atleast one non linear element. what does this mean ? also, can i use different
Hello I've download (using google) the TX-2B/RX-2B datasheets, 120627 I will focus on the crystal oscillator built around Q1: 120628 I have a toy car, the transmitter unit is working on 3 Volt. It's a replica for the circuit in the datasheets. Only diffe
Hi guys! I like to present a power oscillator working at around 2 MHz. It consists of a CMOS oscillator made from CD4069 IC. The inductor driven by Q7 is a loop shaped antenna. It has a diameter of about 5cm and has 15 turns. You may experiment with different antennas. Several Watts of output power may be obtained. 119744
There are many mistakes in especially varicap controlled oscillator. There are 2 resonance point, varicaps are floating,phase shift ???
2SC4367 has a typical transit frequency of 1 GHz (min. 600 MHz), so you're lucky if the circuit is oscillating at 900 MHz at all. You all want to use transistor with GHz bandwidth instead. Apart from this point, what's the value of C2? Is your circuit layout suited for 900 MHz at all? If you connected an antenna, it's frequency dependent radi
You should go for gm/Id methology to determine the optimum W/L ratio of each transistor. It also give a vivid picture to the region of transistors. So go for it.... Hello everyone, I am trying to design a starved current ring oscillator based with CMOS 0.35u having to emit 100MHz. I dont have much power limitation (meani
Hi masters.i have a hartley circuit based on transistor ,my problem is when i change the value of L1 and L2 to a " uH " value for instance L1=L2=1uH the output wave is nothing while it works for L1 and L2 in "mH" values for instance it works when L1=L2=1mH ,WHY? how i can make it work for L1 and L2 in uH values?I changed C1 value according to L1 &
I need to design an oscillator, by using colpitts which will oscillate from 100 MHz to 400 MHz. The circuit should also be able to produce an output signal ranging from 100 mV to 1 V peak voltage at 100MHz. However I have simulated and the output signal is not even 100mV. Any way that I can solve it? 113224
Hye all..I'm doing a project for my degree now. The project is about designing the oscillator wave with centered frequency at 13 GHz. I decided to use GaAs MESFET NE71383B as my transistor. 112034 The problem is, when I look into the schematic diagram of that transistor, there are another transistor place in it, la
Very nice but how come it has a 50MHz crystal but transmits on an unrelated frequency. 166.9MHz isn't harmonically related or are you using one transistor as a mixer with a different oscillator? Brian.
Perhaps Orcad calculates based on a reversed biased cap, whereas Proteus does not.? I don't believe that polarized capacitors are modelled specifically at all. Trivial explanation, 1 ms simulation time in Orcad is just too short to see oscillations. In addition, you might stumble upon a standard oscillator simulation problem.
111197 Dear ravch.. I think there is a fundamental error in your oscillator circuit.You have used a transistor with 2 Source pins that are practically parallel but these Source pins are connected to GND via different paths. This will create problem because while one side is acting series feedback circuit with a series c
there are a number of papers out there that add an automatic level control to the oscillator to limit how much the transistor goes into compression. You could try that. One of the first pieces of test equipment Hewllet and Packard made in their garage was a very low distortion audio oscillator. It worked by having high gain to start (...)
I do not know what is "passive feedback". Active feedback is used as positive feedback in an oscillator or to make very fast Schmitt Trigger switching. Active feedback is also used as negative feedback in a transistor or opamp amplifier to reduce distortion and increase high frequency response.
Hi all I'm having a hard time identifying this transistor. From the circuit function and layout, I figured that it is an oscillator working around 2 GHz. There is a little piece of transmission line connecting the gate to ground. The drain is biased at 2.5 V and the source is pulled down to -1V or so to turn on the transistor, and then (...)
The schematic in black is a simple crude circuit. Crude means cheap with poor performance and probably poor reliability. It is a single transistor oscillator driving the transformer that gives its positive feedback.
In a recent thread you asked if the oscillator transistor in a radio transmitter mechanically oscillates! I answered that the transistor is in an oscillator circuit with no moving parts. I said the electrons go back and forth. Now you are asking about how does a radio transmitter work, but it is obvious that you have not (...)
Why does this simple oscillator circuit need a transistor? A theoretical model of an oscillator consists of an active element achieving a gain (much) greater than the unity - generally represented by a block called 'A' - and a passive resonant element which performs the feedback for the desired frequency - generall
EDIT: A piezo beeper is a piezo transducer with a transistor oscillator inside. The transducer beeps when the oscillator is powered by a DC voltage. The output of the 555 produces a buzzing tone when there is light. The 555 in the circuit is overloaded by most low impedance
Using a Mosfet with a very high value timing resistor and a very low leakage capacitor, the beeper will receive its power supply voltage very slowly then its oscillator might not begin the beeping. The 555 or another monostable circuit will suddenly apply power to the beeper to ensure it begins beeping. A 3V supply is needed so the 555 should be a
The phase-shift oscillator gives a sinewave output. The multivibrator gives a squarewave output. Didn't you want 1Vp-p square(wave)? The output level of the multivibrator is almost the supply voltage when there is no load.
The three RC phase shift parts create a total of 180 degrees of phase shift which is used for positive feedback and the inverting transistor causes the remaining needed 180 degrees of phase shift. The phase shift parts cause an attenuation of about 29 times. The voltage gain of a single transistor phase shift oscillator must be limited to a (...)
The principle of common-base operation is that we change voltage at the emitter, thus turning the transistor on and off. I searched through my large collection of oscillator schematics which use one or two transistors. I had trouble finding one that illustrates common-base operation. In particular I was looking for a capacitor (or LC tank) (...)
A phase-shift or Bubba oscillator works MUCH better when opamps are used instead of transistors. Because an opamp has a very high input impedance and a very low output impedance.
You could use a divide by three counter, driven by your 555 oscillator. You could use three 555s monostables each one firing the next . Frank
A Varicap is a variable capacitance diode where the amount of its reverse voltage determines its capacitance. When it is parallel with an inductor then the LC in an oscillator can be an FM modulator. A simple transistor can also be used as a varicap and the transistor is the oscillator. You can find FM demodulator circuits (...)
The transistor is a "common-base" amplifier. Its collector feeds positive feedback to its emitter through C2. Some websites call the oscillator a "Colpitts" type.