Results 1 to 4 of 4

Thread: How does PWM work?

  1. #1

    Default How does PWM work?

    Searched and found the question, but not the answer. This is probably obvious, but want to confirm. If I have PWM Output set to 100 Hz and the Duty Cycle is 50%, does this mean that it sends 50 pulses of .01s duration per second? 75% would be 75 pulses of .01s duration per second? 100% would be 100 pulses of .01s duration per second (i.e. continuous)? Thanks.

  2. #2


    A "normal" square signal will have half of the time high state and the other half off state. This is 50% duty cycle. At 0% will be always off and at 100% always on.
    Last edited by Pacha; 07-24-2019 at 02:34 PM.

  3. #3
    Join Date
    Dec 2009


    There's some graphical examples on pages 15-17: (V4 Software/Firmware Update Overview)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  4. #4


    Thanks for the responses. I think the link is wrong as the charts are focused on Timers, but I think I get the idea now.
    25% at 100 Hz would have 100 .0025s *on* cycles per second (and 100 .0075s *off* cycles)
    50% at 100 Hz would have 100 .005s *on* cycles per second (and 100 .005s *off* cycles)
    75% at 100 Hz would have 100 .0075s *on cycles per second (and 100 .0025s *off* cycles)
    100% at 100 Hz would have 100 .01s *on* cycles per second (always on). Thanks again.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us