Oscillator buffer

Started by o pere o in sci.electronics.design10 years ago 38 replies

The thread related to large signal PSpice models and an emitter follower comes from the following problem: I have an oscillator that should...

The thread related to large signal PSpice models and an emitter follower comes from the following problem: I have an oscillator that should drive a digital part of the system. In short, what is the best way to achieve this? My first attempt has been a common base Colpitts oscillator that gives a signal riding on the +Vcc rail. This has been AC coupled to a 74AC gate biased to the poin...


LM386 oscillator challenge

Started by bitrex in sci.electronics.design7 years ago 21 replies

So here's a schematic of a standard LM386 power oscillator: http://www.interfacebus.com/lm386-square-wave-oscillator-circuit.jpg I have an...

So here's a schematic of a standard LM386 power oscillator: http://www.interfacebus.com/lm386-square-wave-oscillator-circuit.jpg I have an idea for a thing where what I'd like to have is a second LM386 oscillating at the same frequency and amplitude, but opposite phase as the first one, for push-pull drive. But I'd like to not use any further active parts other than the second LM386, if...


CD4093 oscillator frequency

Started by bitrex in sci.electronics.design7 years ago 33 replies

I'm buidling a little relaxaton oscillator for a project using a cd4093 quad nand gate with schmitt trigger inputs. I'm using a 200 ohm...

I'm buidling a little relaxaton oscillator for a project using a cd4093 quad nand gate with schmitt trigger inputs. I'm using a 200 ohm resistor and a 100n cap in the RC network. If I've done my calculations correctly, I was hoping to have an oscillator at around 30kHz. But my frequency counter is only showing around 8. Supply voltage is 5V. I understand that the frequency is depe...


How to select transistor for oscillator ?

Started by Anonymous in sci.electronics.design4 years ago 45 replies

Could some electronics guru here please help ? What is the best way to select a transistor for an oscillator ? Consider a Colpitts oscillator...

Could some electronics guru here please help ? What is the best way to select a transistor for an oscillator ? Consider a Colpitts oscillator running at 5 MHz. The following are the analysis steps. 1. Select a value for the LC tank capacitor C1 = C2 = C 2. Select a load e.g., R=50 Ohm 3. To start oscillations, gmR > C2/C1. In this case gmR > 1 4. Using the oscillation frequency and


Magamp oscillator

Started by Piotr Wyderski in sci.electronics.design7 years ago 128 replies

Is it at all possible to build an oscillator entirely from non-linear magnetics (OK, solid state diodes are allowed)? Best regards, Piotr

Is it at all possible to build an oscillator entirely from non-linear magnetics (OK, solid state diodes are allowed)? Best regards, Piotr


A bit of help with a crystal oscillator

Started by Peter in sci.electronics.design3 years ago 67 replies

I have read a lot of stuff on this topic but find it hard to apply it. I have a 25MHz xtal. For example Kyocera CX3225GB25000P0HPQZ1. The spec...

I have read a lot of stuff on this topic but find it hard to apply it. I have a 25MHz xtal. For example Kyocera CX3225GB25000P0HPQZ1. The spec says typ drive level 10uW, 100uW max. The oscillator circuit is the usual Pierce one as in e.g. here https://electronics.stackexchange.com/questions/368945/crystal-oscillator-circuit-design?rq=1 The CPU is a STM32F407VGT6. The development ki...


Low-voltage AC-powered oscillator

Started by Piotr Wyderski in sci.electronics.design6 years ago 23 replies

If the power supply voltage is high, say > =3V, it is pretty simple to design an oscillator (of unimportant output frequency and shape), which...

If the power supply voltage is high, say > =3V, it is pretty simple to design an oscillator (of unimportant output frequency and shape), which can be powered from an AC power source: just add a diode bridge at the power input lines and use any suitable DC-powered oscillator circuit. But what if the supply voltage is really low, say 0.2V? JFET-based oscillators can go really low, allegedly down


Quadrature Oscillator

Started by George Herold in sci.electronics.design8 years ago 49 replies

Quadrature oscialltor. Hi all, As part of the CV measurements (from a previous post) I'm thinking about a 1 MHz lockin. (Maybe a different...

Quadrature oscialltor. Hi all, As part of the CV measurements (from a previous post) I'm thinking about a 1 MHz lockin. (Maybe a different thread to talk about how to do the switching.) I was wondering if I could make a quadrature oscillator from opamps. (I've got some AD825's I thought I'd try.) Anyway spice seems to think it's possbile. Comments or ideas welcome. (Oh I had to add th...


Heck of a way to run an oscillator?

Started by skeptical engineer in sci.electronics.design8 years ago 44 replies

I was looking at the SAW oscillator circuits at a co. called Epcos, and they just take an op amp with the SAW filter in the feedback loop....

I was looking at the SAW oscillator circuits at a co. called Epcos, and they just take an op amp with the SAW filter in the feedback loop. They explain that the op amp amplifies noise, but preferentially at the filter allowed frequency. 2 components. I love the simplicity, but does this approach have any drawbacks?


GHz oscillator

Started by John Larkin in sci.electronics.design1 year ago 55 replies

What's a good way to make a, say 2 or 3 GHz sinewave oscillator? I don't need extreme accuracy, and I'd like maybe 1 volt p-p. I was thinking...

What's a good way to make a, say 2 or 3 GHz sinewave oscillator? I don't need extreme accuracy, and I'd like maybe 1 volt p-p. I was thinking a cheap MMIC with PCB delay line feedback. MiniCircuits VCOs are around $20, which isn't bad. The output would go into a PWM modulator and then an AC-coupled communications channel.


dual gate mosfet oscillator

Started by bitrex in sci.electronics.design9 years ago 22 replies

Anyone have any experience with how dual gate mosfets perform in a crystal oscillator role, at low voltages ( < 3 v), at frequencies say 200...

Anyone have any experience with how dual gate mosfets perform in a crystal oscillator role, at low voltages ( < 3 v), at frequencies say 200 - 500 MHz? -- ----Android NewsGroup Reader---- http://www.piaohong.tk/newsgroup


The HP Original for sale

Started by bitrex in sci.electronics.design5 years ago 33 replies

HP 200C Wein Bridge oscillator up for sale on eBay. $125. "Thank You For Looking At Are Item"

HP 200C Wein Bridge oscillator up for sale on eBay. $125. "Thank You For Looking At Are Item"


oscillator for driving a transformer

Started by panfilero in sci.electronics.design10 years ago 12 replies

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable...

Hello, I'd like to drive a small high frequency transformer at around 100kHz-300kH= z with a 24Vpk signal, I tried building up an astable multivibrator with a = couple of caps and transistors but i couldn't get it to drive the transform= er, it wouldn't even make anything close to a nice square wave.... anyone k= now of a better simple oscillator circuit I could use to do this? thanks! ...


it oscillates!

Started by Anonymous in sci.electronics.design2 years ago 54 replies

During this shutdown, I did a little pcb layout for my triggered common-collector Colpitts oscillator, and had some boards fabbed....

During this shutdown, I did a little pcb layout for my triggered common-collector Colpitts oscillator, and had some boards fabbed. A manufacturing person came in today and built a couple for me. It's a triggered 125 MHz oscillator that will be used to time delays in a laser system. We want minimal time jitter so I tried to keep the Q up. The inductor is a Coilcraft Midi-Spring. I used ...


Relaxation oscillators and SPICE

Started by Piotr Wyderski in sci.electronics.design8 years ago 25 replies

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and...

I am unable to simulate the followingg PUT-based relaxation oscillator in the most recent LTspice (with BC547B and BC557B): https://upload.wikimedia.org/wikipedia/commons/9/9f/PUT_LED_blinker.png Nothing wants to oscillate. Looking for a bug I have also tried the simplest possible neon lamp oscillator (with Vstrike=100V, Vhold=50V, R=220k, C=1u), but there are no scillations either: ...


LTSpice simulator of my oscillator is far from reality; bad models?

Started by Clifford Heath in sci.electronics.design8 years ago 25 replies

Folk, Thanks to some good help here in the past, I have a nice clean oscillator (for my new fox transmitters), but I'm having trouble with...

Folk, Thanks to some good help here in the past, I have a nice clean oscillator (for my new fox transmitters), but I'm having trouble with the LTSpice simulation at higher frequencies. I'm assuming that the Intersil Spice model for the CA3046 is bad, and I know JT has a better one. Anyhow, I have two questions about the attached LTSpice schematic. 1) When I set it to 30MHz, LTSpice ...


Transformer/excitation coil for Armstrong oscillator

Started by Anonymous in sci.electronics.design4 years ago 11 replies

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to...

Could some electronics guru on this group please help ? I am trying to set up a SPICE simulation for an Armstrong oscillator. The problem seems to be with designing the transformer and/or excitation coil. Are there any good tutorials or related material online. Any hints/ suggestions would be of immense help. Thanks in advance.


Help With Royer Oscillator

Started by Kooner in sci.electronics.design11 years ago 19 replies

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by...

Hello, I have a working Royer Oscillator. This version is not current fed. It is a push push tolpolgy and the LC oscillationis are set by the transformer inductance and winding capacitance. The schematic looks like a multivibrator except the reistors in the collectors are replaced withthe half primaries of the pushpull transformer. This circuit has BJTs and has a sine wave output but I w...


Hartley Oscillator: Two Coils, No Cap

Started by Kevin Foster in sci.electronics.design6 years ago 17 replies

Would it be possible to build a single transistor Hartley oscillator by substituting a pancake (spiral) coil for each leg of the center-tapped...

Would it be possible to build a single transistor Hartley oscillator by substituting a pancake (spiral) coil for each leg of the center-tapped inductor, and then placing one coil flat on top of the other so the insulation between them takes the place of the cap? If the current in each coil is made to flow opposite to the other, could their proximity to each other also be used to vary th...


A Brief Review of RF Oscillators in LTspice

Started by Steve Wilson in sci.electronics.design4 years ago 11 replies

Some people struggle to try to get an oscillator running in LTspice. This article describes different types of Colpitts and Clap oscillators snd...

Some people struggle to try to get an oscillator running in LTspice. This article describes different types of Colpitts and Clap oscillators snd shows how to calculate the component values to get them to run. Crystal oscillators are discussed, along with a method to drastically shorten the startup and settling time in order to view the actual oscillator waveforms. The descriptions are a...