16 votes

Simplest practically buildable oscillator

There's always the relay oscilator. If you want to make it have a specific frequency you can add resistors and capacitors, but it will oscillate just fine like this, and make quite a racket.
QuadmasterXLII's user avatar
10 votes

Sine oscillator at extremely high frequencies

One cannot build such an oscillator. You need different technologies to find something that electronically oscillates at 50 GHz, which is still RF, possible to work with in semiconductor electronics, ...
sina bala's user avatar
  • 556
6 votes

Sine oscillator at extremely high frequencies

The frequency classes you are interested in are SHF and EHF and range from 3GHz to 300GHz. To create something that works in such frequency bands, new knowledge such as microwave engineering with ...
Franc's user avatar
  • 826
5 votes

Simplest practically buildable oscillator

This circuit has only two parts plus a delay line which could be a piece of coax or a pattern on a PCB- it depends on an obsolete part (a tunnel diode), but it's not impractical to build as an ...
Spehro Pefhany's user avatar
4 votes

How do I achieve the desired frequency with a Colpitts oscillator?

I would like to build an oscillator with frequency variation from 50 MHz to 100 MHz With a trimmer that goes from 8 pF to 30 pF in series with a 200 pF (C4), the net capacitance is from 7.69 pF to 26....
Andy aka's user avatar
  • 452k
4 votes

If many radio waves can generate currents in the antenna ground circuit **simultaneously** I am wondering do they all get carried over to the tuner?

Red, green, and blue light reach your eye simultaneously. If you put a red filter in front, you'll only see the red light. The tuner is a filter that picks out the "color" of radio wave you ...
John Doty's user avatar
  • 3,874
4 votes

Sine oscillator at extremely high frequencies

For the frequency range you speak of, we don't really have good solid dielectrics. So you'll need waveguides and related hardware just to get the output of the oscillator to wherever the load is. I ...
Kuba hasn't forgotten Monica's user avatar
3 votes

Sine oscillator at extremely high frequencies

Let's break down you problem a little bit: We start at 50 GHz. 50 GHz is already an extreme frequency to work at. However, it is possible and there is measurement equipment commercially available to ...
GNA's user avatar
  • 1,591
3 votes

Simplest practically buildable oscillator

Since there are no constraints on frequency stability and variability, I'd like to propose a few other alternatives: A microcontroller with an onboard oscillator, programmed to output a frequency of ...
DSVF's user avatar
  • 179
3 votes
Accepted

Equivalent impedance for R-C configuration in op-amp input

The key here is that the inverting input of the OpAmp is a "virtual ground". When the circuit is in regulation (closed-loop), the OpAmp regulates the voltage at the inverting input to be ...
Jonathan S.'s user avatar
  • 17.8k
2 votes
Accepted

If many radio waves can generate currents in the antenna ground circuit **simultaneously** I am wondering do they all get carried over to the tuner?

Whatever frequencies the antenna picks up get fed into the radio. Typically in the receiver front end there will be a tuned circuit that filters out most of the signals. To get selectivity narrow ...
GodJihyo's user avatar
  • 22k
2 votes

LM318 strange oscillations

You need a capacitor from pin 4 to pin 7 near the chip and no capacitor on the output (also inverting and non-inverting are switched, but that was a transcription error you said). In fact, put a 100Ω ...
Spehro Pefhany's user avatar
2 votes
Accepted

LM318 strange oscillations

Your op-amp inputs are connected incorrectly for a relaxation oscillator: - Positive feedback via the 10 kΩ resistors should be to the non-inverting pin like this: - Image above from here. You also ...
Andy aka's user avatar
  • 452k
2 votes
Accepted

Sine oscillator at extremely high frequencies

You're still way off in your technological estimate of what's doable. At 50 GHz, a 10 pF load is pretty much impossible to drive: |X|=|1/(j2πfC)|, for f=5×10¹⁰ Hz and C=1/10¹⁰ F, is |X|=1/31.4 Ω. At 2 ...
sina bala's user avatar
  • 556
1 vote

How do I achieve the desired frequency with a Colpitts oscillator?

A good start The basic circuit is very similar to Heathkit HD-1250 "gate"-dip oscillator. Be aware that designing for octave frequency range (50MHz - 100 MHz) is not easy. One of Heathkit's ...
glen_geek's user avatar
  • 25.3k
1 vote
Accepted

Problem with LR oscillator

I tried your circuit in the CircuitLab simulator and it basically works. Because the typical NPN transistor allows only a reverse Vbe of around -5 V I changed the supply configuration. The H-bridge ...
Jens's user avatar
  • 6,739
1 vote
Accepted

Do we need to provide same voltage for microcontroller I/O and oscillator?

This is an ARM MCU and like most of them, it is no different. The IO pins which are used for crystal are standard GPIO pins unless software decides to configure them for crystal use. The GPIO pins ...
Justme's user avatar
  • 144k
1 vote

Simplest practically buildable oscillator

Up to you what you think about this but the Soviet amateur circuits frequently depicted an 8 MHz oscillator working on the part of K155LA3 chip (analogue of 7400PC) without any additional elements. It ...
h22's user avatar
  • 850

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