Which Switching Device can Switch from Off to On and Off the fastest?

  1. Transistor
  2. Solid State Relay
  3. or Mechanical Relay
  • \$\begingroup\$ What's the purpose of the switch? What are you ultimately trying to accomplish? \$\endgroup\$ Jan 7, 2016 at 8:43
  • \$\begingroup\$ what do you think is likely to switch faster? A lump of metal or charge carriers in a piece of semiconductor? \$\endgroup\$
    – Icy
    Jan 7, 2016 at 8:45
  • \$\begingroup\$ @NickAlexeev Im trying to find what device is most suitable for quick changes in the power \$\endgroup\$
    – Bryan
    Jan 7, 2016 at 10:02
  • \$\begingroup\$ @Icy what about the difference between solid state relays and transistor? \$\endgroup\$
    – Bryan
    Jan 7, 2016 at 10:07
  • 2
    \$\begingroup\$ Your question is being downvoted because it is NOT specific. Without any details about the amount of voltage or current you want to switch, it's far too broad. Also, "the fastest" is far too vague -- are you talking about the speed of a single transition, or the overall repetition rate? If you gave us some context about what you're actually trying to accomplish, we'd be able to provide specific advice. \$\endgroup\$
    – Dave Tweed
    Jan 7, 2016 at 16:53

2 Answers 2


Transistors are used in extremely high frequency radio amplifiers and transmitters (we're talking frequencies that are many GHz). They are also used in very high speed devices such as CPUs, FPGAs, logic devices and the list of high speed devices goes on and on.

Solid state relays are quite often used to turn on and off an appliance connected to a 50 or 60 Hz power AC supply as are mechanical relays. However mechanical relays need to physically move an armature to perform a switching action.

Based on what I've said, what do you think is the fastest device.


Speed of switching vs Component. Time 0-------------------------------------------------Eternity (~25mS)

Transistor |***** SSR |******* Relay |***************************************************************>> Capiche?


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