pwm

  1. C

    Converting 24vdc PWM to logic level for motor driver

    Hi, I have a PLC that I'm trying to send a PWM signal out to a DC motor driver for varying speed. My PLC output signal is 24VDC sinking type and I vary the duty cycle from 0-100% over a pre-selected set frequency. I can connect a small DC motor directly and control speed nicely. But I have...
  2. F

    Running multiple 12v motors of one PWN controller (help required)

    Hi there, First off a bit of background, this is part of a university project where I want to control the flow of water from a reservoir into 12 small tanks (the flow going into each of the 12 tanks needs to be the same, roughly 30ml/min). My way of achieving this is to use 12 peristaltic...
  3. 4 x manual set timer for pump control

    Hi All, Total Newb here in respects, but have soldered boards before and have an extremely basic understanding of electronics. I am would like to design a pump timer with 4 separate settable pot timers; 1 timer On for X seconds 1 timer On for Y seconds 1 timer On for A seconds 1 timer On for...
  4. J

    H-Bridge Amp for 8Ω Speaker (PWM)

    I am using fairly robust D882 and B772 transistors in my design, so I am wondering if I still need 4 damper diodes to protect the transistors as shown below? (Leaving them out saves a little on space and cost.)
  5. Interfacing Arduino with LM3915

    After searching the internet, I got a lot of clues but no answer. Here is the answer. The LM3915 bar / dot display driver wants an analog input up to 1.25 volts where the tenth LED comes on. Arduino analog output is actually PWM at 5 volts, using a 5 volt supply. This gets a smooth voltage...
  6. N

    DC fans creating electronic noise issue

    Hi! In order to cool a telcom device I am using 4x 12Vdc fans from Delta Electronics (the exact type is FFB0412VHN-F00). The fans have a 3-wire interface and I operate them by sending PWM pulses at their power supply wire. The pulses are generated from a PIC-microcontroller and are "converted"...
  7. R

    PWM and Filter LC

    Hello, I am creating a PWM signal by comparing a sine wave (50Hz) and a triangular wave arrier (10kHz) ,in ordem to control a full bridge inverter. II had been try filter this pwm signal to obtain a sinusoide, with a LC filter. I use this equation to find a cut-frequency of the filter (and...
  8. 18F4431 - setting pins as plain IO

    Micro 18F4431 - Assembly In spite of having used the above, several times in the past with no issues, today, after replacing in a working design, the 18F452 in charge with a 18F4431, I found the keyboard and LCD, not responding. After much RTFM, I noted that pins RB0 / PWM0 RB1 / PWM1 RB2 /...
  9. R

    20Khz+ PWM high-wattage LED producing too much heat

    I'm working on dimming a high-wattage LED (50W--12V/4.17amps) with a 3.3V micro-controller. The solution that has worked so far is by using a low-side (PNP) MOSFET to drive the LED and a NPN transistor to drive the MOSFET via the 3.3V signal from the MCU. At 488hz PWM I can dim the LED light...
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