Electronics notes/frequency generation

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This is for beginners and very much by a beginner.

It's intended to get an intuitive overview for hobbyist needs. It may get you started, but to be able to do anything remotely clever, follow a proper course or read a good book.


Some basics and reference: Volts, amps, energy, power · Ground · batteries · resistors · changing voltage · transistors · fuses · diodes · varistors · capacitors · inductors · transformers · baluns · amplifier notes · frequency generation · skin effect


And some more applied stuff:

IO: Input and output pins · wired local IO wired local-ish IO · · · · Shorter-range wireless (IR, ISM RF, RFID) · bluetooth · 802.15 (including zigbee) · 802.11 (WiFi) · cell phone


Sensors: General sensor notes, voltage and current sensing · Knobs and dials · Pressure sensing · Temperature sensing · humidity sensing · Light sensing · Movement sensing · Capacitive sensing · Touch screen notes

Actuators: General actuator notes, circuit protection · Motors and servos · Solenoids

Some stuff I've messed with: Avrusb500v2 · GPS · Hilo GPRS · JY-MCU · DMX · Thermal printer ·


Audio notes: microphones · device voltage and impedance, audio and otherwise · amps and speakers · basic audio hacks · digital audio ·


Less sorted: Common terms, useful basics, soldering · Arduino and AVR notes · ESP series notes · PLL · signal reflection · pulse modulation · electricity and humans · resource metering · Microcontroller and computer platforms · SDR · Unsorted stuff

See also Category:Electronics.

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Oscillators, resonators, crystals, and such.

Applications include:

  • clock source (for digital elements, digital communication)
  • reference clock
  • signal generator


In basic electronics you mostly see ceramic resonators (cheap, can be used when timing is not critical), basic quartz crystal oscillators (more accuracy than resonators), and corrected quartz crystal oscillators (more accuracy than basic quartz; necessary for some applications)


Accuracy refers to how much it adheres to specification, and how much it may vary (e.g. due to temperature).



  • ceramic resonators are less accurate than crystals, but good enough whenever timing need not be that accurate
    • frequency tolerance: on the order of 0.5% (5000ppm) (7.2min/day)
  • crystal oscillators - piezoelectric quartz.
    • frequency tolerance: on the order order of ~0.001% (~10ppm) (~0.86sec per day)
    • Tunable within a small range of frequencies
    • Fairly cheap
    • not accurate enough for certain some applications (such as some radio transmission, long-term timekeeping, stability under varying temperatures)



  • Low-Frequency Oscillator (LFO) - designs that generates a waveform below ~20 Hz. Used in synthesizers and such.
  • Surface acoustic wave (SAW) oscillators - quartz crystals that achieve higher frequencies though a standing-wave construction. More expensive, but necessary for devices that
    • frequency tolerance: on the order of 0.0001


  • harmonic/linear, oscillator (waveform like a sine wave) [1]
  • relaxation oscillator (waveform like a sawtooth) [2]


Furter types:

  • TCXO (temperature-compensated crystal oscillator)
    • less than 5 PPM, down to 0.1 PPM is theoretically possible. A little more complex than basic crystals.
    • TCXO often implies analog TCXO (sometimes ATCXO)
    • DTCXO is digital TCXO
  • MCXO (microcontroller-compensated crystal oscillator)
    • refers to designs that are more stable and avoid more noise and drift (useful when supporting less predictable things like uCs) (verify)
    • Down to 0.1PPM



See also: