31 votes
Accepted

Why not put a crystal oscillator inside the microcontroller?

A crystal is very different in physical construction from an MCU, and most crystals are annoyingly large to integrate into a chip package. It's possible, however, to integrate other types of (smaller) ...
nanofarad's user avatar
  • 20k
23 votes

Why not put a crystal oscillator inside the microcontroller?

A crystal is fabricated on a completely different process and from a completely different material than a microcontroller is. You can't integrate them both into a single chip, so you would have to ...
Hearth's user avatar
  • 32.6k
23 votes

Simplest practically buildable oscillator

Pearson-Anson oscillator Neon bulb, resistor, capacitor, voltage supply high enough to light bulb. The capacitor charges through the resistor, when the voltage across it reaches the neon bulb's ...
GodJihyo's user avatar
  • 23.4k
23 votes

Ethernet port as a signal generator

Is it technically possible? No. Highly specialized hardware, relatively specific coupling, and a very limited set of amplitudes actually imposable on the line make that infeasible. Don't get me wrong:...
Marcus Müller's user avatar
16 votes

Why not put a crystal oscillator inside the microcontroller?

Here's a crystal oscillator (source): In order to work, a crystal must be suspended in free air (or inert gas) by the edges. It works like a tuning fork, it is a mechanical resonator with electrical ...
bobflux's user avatar
  • 77.6k
16 votes

Simplest practically buildable oscillator

This is the simplest I know. Frequency is independent of devices (CMOS with 1/3 2/3 level trigger points) and supply voltage. simulate this circuit – Schematic created using CircuitLab
MOSFET's user avatar
  • 3,110
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

How can I make an LED strobe light for a turntable to replace a glimm light?

Honestly, the analogue way with diodes and using the AC frequency is a much better way to do this. The digital way here is just to explain the original example given in the question, or if you want ...
jonathanjo's user avatar
10 votes

Why not put a crystal oscillator inside the microcontroller?

The main reason is that MCUs and crystals use very different production processes. One is silicon etching in a photochemical process and the other is a mechanical machining one. Often you can't even ...
DKNguyen's user avatar
  • 56.7k
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
  • 603
9 votes

Simplest practically buildable oscillator

Simplest is a CMOS ring oscillator. You only need a CMOS IC with three (or five, or any odd number of) inverters connected in a ring. Of course, power supply and bypass caps should be applied, and it ...
Justme's user avatar
  • 149k
8 votes

Why is my crystal oscillator (4 pin DIP 4 MHz unbranded from ebay) producing unusable clock signal waves?

The oscilliscope you linked to has a 200 KHz bandwith - it will not show anything near the correct waveform and voltages of a 4 MHz signal.
Peter Bennett's user avatar
8 votes

Why not put a crystal oscillator inside the microcontroller?

One issue with adding a crystal to a microcontroller is thermal considerations. The frequency of crystal oscillators varies with temperature, and they are typically tuned to be their designed ...
user's user avatar
  • 1,881
8 votes
Accepted

Why is the frequency and voltage of my Colpitts oscillator lower on breadboard than LTSpice?

A breadboard will have capacitance between the connection rows. The jumper wires will have inductance. Real components will have parasitic resistance, inductance and capacitance that a simulation may ...
GodJihyo's user avatar
  • 23.4k
7 votes
Accepted

Running multiple ICs with a single crystal

The ADC you describe supports the use of a CMOS clock signal, as well as the use of a passive crystal. While you state that your selection of available components is limited, basic logic gates may be ...
Kaz's user avatar
  • 468
7 votes

Regulating output of 555 astable oscillator

Build the circuit the other way around i.e. First 12V to 5V with 317, then drive the oscillator with 5V. Alternatively, you can drive 555 with 12V directly and use a divider (or a resistor+Zener) at ...
Rohat Kılıç's user avatar
7 votes

PIC MCU wont accept external oscillator

You are trying to build a sensitive crystal oscillator on a breadboard. You also have no bypass caps at all on the power supply. I would not expect it to work. You have long jumper wires and the ...
Justme's user avatar
  • 149k
6 votes

Is this supposed to be the output of this circuit?

The first problem is that the DC output level feeding the primary inductor MUST BE 0 volts. However, your push-pull output is delivering (or trying to deliver) an average voltage level at around 10 ...
Andy aka's user avatar
  • 457k
6 votes

Simplest practically buildable oscillator

For simplicity, to make a sine wave output, you can stick a magnet to a tuning fork and hold a coil of wire next to it after striking. It'll oscillate a while; sometimes just a few seconds is all ...
Whit3rd's user avatar
  • 7,588
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
  • 1,261
5 votes
Accepted

1.5 to 9 V transistor boost converter issue

The original poster may have since moved onto something different, but the information may still be helpful to others. It may be more practical building a simple flyback type converter as seen in the ...
DM2236's user avatar
  • 211
5 votes

How can I make an LED strobe light for a turntable to replace a glimm light?

Your turntable has 18V AC available. That allows for a very simple circuit: simulate this circuit – Schematic created using CircuitLab Adjust R1 to control the brightness. Adjust the number of ...
Janka's user avatar
  • 14.3k
5 votes
Accepted

Using inductor on PCB component power rails

They are not chokes in the traditional sense. They are ferrite beads. The designator is FB, and ferrite beads are rated for their impedance at 100 MHz, here 220 ohms. Ferrite beads are used as filters....
Justme's user avatar
  • 149k
5 votes

Ring Oscillator

Assuming a CMOS inverter: This can't work, but not because Barkhausen's criterion is violated – it just doesn't apply; this isn't a network consisting of an amplifier and a phase-shift network, it ...
Marcus Müller's user avatar
5 votes
Accepted

Unable to get my astable multi-vibrator working in LTspice

Here is one problem: The output of the op-amp is connected to GND. There may be other problems.
Fabio Barone's user avatar
  • 2,304
5 votes

Why not put a crystal oscillator inside the microcontroller?

Total system cost would be higher than with an external crystal. The IC supplier would have to source the crystal from another supplier most likely, one who could guarantee supply over the life of ...
Spehro Pefhany's user avatar
5 votes
Accepted

MOSFET ring oscillator LT SPICE

Of course, you are not seeing any oscillations, as you use a default N/PMOS model, and this model is the Shichman-Hodges model, threshold-based model, which does not model device capacitances. You can ...
V.V.T's user avatar
  • 4,242
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
5 votes

Ethernet port as a signal generator

I doubt it: Ethernet is a specialized medium, and line control, framing, etc. are built in to the interface (the MAC). Needless to say, you'd also need the driver-level hardware documentation, and a ...
Tim Williams's user avatar
  • 34.2k

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