Linear regulator

Started by Jonas in sci.electronics.basics8 years ago 6 replies
PWM

Hello HAs anyone ever tried to use a linear regulator to regulate a PWM signal? My situation: Input signal, 24V PWM 400Hz I want to have...

Hello HAs anyone ever tried to use a linear regulator to regulate a PWM signal? My situation: Input signal, 24V PWM 400Hz I want to have 12V PWM signal 400Hz I was thinking of using a linear regulator (type LM317) and use the 24V PWM as input and get 12V PWM on the output, does anyone know of any problems related to this (lifelength, EMC etc). /Jonas


thinking about a 200 amp 12v pwm controller

Started by izzi in sci.electronics.basics9 years ago 2 replies

I"ve started looking into putting together around a 200-250 amp 12v pwm controller for a DC drive i have. I've got the pwm driving aspect of...

I"ve started looking into putting together around a 200-250 amp 12v pwm controller for a DC drive i have. I've got the pwm driving aspect of this down aside from the mosfet selection and dealing with the heatsinks that i'll be stuck using. Anyone ever put something along these lines together before? The cycle time will be low around 1 min on and very long time off. 30min+ range, this s...


PWM controlled current sink for LED backlight.

Started by Sean Peters in sci.electronics.basics9 years ago 12 replies

Hello, I have a monitor with a LED backlight that uses PWM to directly switch on/off the LEDs to vary the brightness. I can't stand the...

Hello, I have a monitor with a LED backlight that uses PWM to directly switch on/off the LEDs to vary the brightness. I can't stand the flicker this produces and want to modify the LED driver to keep the LEDs on all the time, setting the brightness by limiting the drive current, depending on a smoothed version of the PWM signal. I've kind of managed this already, but can't get the ful...


PWM from raspberry pi to control charging of a 12 V Battery, possible?

Started by Anonymous in sci.electronics.basics5 years ago 2 replies

Hi there, I just got a raspberry pi and was wondering if it is possible to use its PWM output to control current flow to a 12 V Battery (with...

Hi there, I just got a raspberry pi and was wondering if it is possible to use its PWM output to control current flow to a 12 V Battery (with an IGBT). My idea is to use a 300 W windmill, a simple AC/DC converter, a IGBT, and the battery at the other side. If voltage is above 13.8V, I reduce the current via PWM to fully charge the battery and disconnect the windmill as soon as the battery ...


Simple PWM Circuit for motor control

Started by Anonymous in sci.electronics.basics11 years ago 9 replies

I need a simple PWM circuit to control a motor from my microprocessor, I found this one: http://home.cogeco.ca/~rpaisley4/LM555.html#17 Any...

I need a simple PWM circuit to control a motor from my microprocessor, I found this one: http://home.cogeco.ca/~rpaisley4/LM555.html#17 Any comments? It looks cheap and simple to build so should fit my requirements.


Adjusting frequency NE556

Started by Dave, I can't do that in sci.electronics.basics9 years ago 13 replies

Hi, The following is a PDF of a motor control kit... http://www.electronickits.com/kit/complete/motor/ck1400.pdf Currently it is designed...

Hi, The following is a PDF of a motor control kit... http://www.electronickits.com/kit/complete/motor/ck1400.pdf Currently it is designed to run at around 410Hz. I assume that too will be the frequency for the PWM output but I need 5KHz from the PWM. I looked at the formula for frequency on page 1 and it may as well be written on Chinese as far as I can tell. Could someone with...


Filtering a PWM signal

Started by Bob Engelhardt in sci.electronics.basics6 years ago 4 replies

I've been watching some of Dave Jones videos (EEVblog). In #225 he discusses using a PWM signal to control the voltage of a power supply. It...

I've been watching some of Dave Jones videos (EEVblog). In #225 he discusses using a PWM signal to control the voltage of a power supply. It needs to be DC to do this, so he uses a filter. He uses a first-order RC filter, with the output going to the "+" input of an op amp. With a 10% duty cycle on the input he shows the output at 10% of the input peak, with some ripple. What I don'...


Driving a PNP Darlington transistor from a PIC16F877A

Started by scouselad in sci.electronics.basics10 years ago 5 replies

Hi, I'm designing an electronically-controlled light dimmer circuit based on one I found at: http://www.edn.com/article/CA46649.html I'm...

Hi, I'm designing an electronically-controlled light dimmer circuit based on one I found at: http://www.edn.com/article/CA46649.html I'm replacing the SG3524 PWM chip with a PIC16F877A and I intend to take a digital input from the user and (scale it, then) compare it with the 0-5V from the op-amp (digitised using the PIC's ADC). As you can see from the diagram, the PWM signal drives a PNP ...


DC motor pwm, mosfet barbecue, etc.

Started by Anonymous in sci.electronics.basics5 years ago 12 replies

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested...

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested it with an automotive turn signal light (about 1 amp) and it worked just fine (without a heat sink on the mosfet). I then tried using it to control a 12V tire inflator/compressor (about 4 amps). The inflator operated fine, but then when I felt the mo...


brushed pwm controller motor "surging"

Started by causalitist in sci.electronics.basics9 years ago 8 replies

i set up a basic lm324 15kz uni-directional pwm motor controller. this goes to a tc4422 mosfet driver and then to 2 irfp4668 mosfets that are...

i set up a basic lm324 15kz uni-directional pwm motor controller. this goes to a tc4422 mosfet driver and then to 2 irfp4668 mosfets that are in parallel. there is one 10 Ohm gate resistor that both fets share .. selected at random since i have no idea why one would use a powerful driver and then reduce its power.(NOT the question at hand) and a gate diode bypassing the gate resistor to all...


how to get this PWM DC motor control to handle more power

Started by causalitist in sci.electronics.basics9 years ago 16 replies

this is the circuit in question, page 3 is the part I'm asking about, not the PWM circuit on page 1,2: http://kitsrus.com/pdf/k166.pdf The...

this is the circuit in question, page 3 is the part I'm asking about, not the PWM circuit on page 1,2: http://kitsrus.com/pdf/k166.pdf The IRF4905 and IRFZ44 limit current to 74A and 49A respectively. The LM324 Quad op-Amp limits Voltage to 32V What is an op-amp that will work here, but be able to handle 100v or maybe 55v min? As far as current and total wattage , I'm looking for min ...


MOSFETs and PWM

Started by Randy Day in sci.electronics.basics11 years ago 41 replies

I've built some TTL motor/relay controllers out of NPN transistors in a Darlington configuration, and I'm considering using mosfets instead. ...

I've built some TTL motor/relay controllers out of NPN transistors in a Darlington configuration, and I'm considering using mosfets instead. +V |_ - )| ^ )| relay |_)| | _R_ |/ TTL in -|___|--| |> | GND (cre


Disassemble cordless drill PWM controller?

Started by John Doe in sci.electronics.basics7 years ago 7 replies
PWM

In a cordless drill (like the DeWalt DCD760), there is a finger grip trigger speed controller. Can that be skillfully taken apart without...

In a cordless drill (like the DeWalt DCD760), there is a finger grip trigger speed controller. Can that be skillfully taken apart without destroying it? I would like to remove the spring. Thanks.


Q. re: "PWM" on Battery Charging IC

Started by Bleep in sci.electronics.basics8 years ago 17 replies

Hello, Group! I am a rube, so thanks in advance for your patience if this is a total-moron- level question ;) I was lookng at a MAX1848...

Hello, Group! I am a rube, so thanks in advance for your patience if this is a total-moron- level question ;) I was lookng at a MAX1848 battery-charge-control IC (the intent is to run the charged batteries to a white LED driver). On the example diagram, this is shown on a portion of the diagram: | ...


Transistor as a current limiter

Started by Lauri Alanko in sci.electronics.basics4 years ago 103 replies

Hello. I need to wire some leds, and I figure that a transistor for each series is a good way to ensure that the leds get constant...

Hello. I need to wire some leds, and I figure that a transistor for each series is a good way to ensure that the leds get constant current, with the additional benefit that I can run PWM through the base of the transistor to control the brightness. However, I'm unsure about the best way to do this. The most common design I see is this: V1 ---- LOAD ---- \Q1-> ---- R1 ---- GND


mosfet? transistor? hexfet?

Started by Anonymous in sci.electronics.basics11 years ago 11 replies

When would one use a transistor? mosfet? hexfet? Basically looking into PWM switching of medium-sized DC motors (12V, ~5A or so). Which...

When would one use a transistor? mosfet? hexfet? Basically looking into PWM switching of medium-sized DC motors (12V, ~5A or so). Which should I use...? A beefy transistor like a TIP36C? Or a hexfet like IRLZ34NPBF (98c at Mouser)? Thanks... Michael


Need for inductive kickback diode

Started by Martin in sci.electronics.basics10 years ago 11 replies

If you are using PWM to control the brightness of an incandescent light, should you use an inductive kickback diode to protect...

If you are using PWM to control the brightness of an incandescent light, should you use an inductive kickback diode to protect the transistor? It is of course recommended to use when you are driving coils, relays, motors, etc. A light is a coil, althought I would guess the inductance is pretty low. Would good practice be to put the diode in "just in case", or its absolutely unneeded?...


Electric Kontiki motor power supply and PWM questions

Started by Anonymous in sci.electronics.basics11 years ago 22 replies

Hello, I'm finally getting around to building an electric fishing Kontiki and have some questions about how to do so. First off an electric...

Hello, I'm finally getting around to building an electric fishing Kontiki and have some questions about how to do so. First off an electric Kontiki is basically a timed torpedo with a prop either at the rear or more recently at under the front to take a line out past the breakers into deeper water where hopefully more and bigger fish lurk. I have a schematic I've drawn up at http://www....


TV remote IR receiver module

Started by pawihte in sci.electronics.basics8 years ago 7 replies

Are TV IR remote control receiver modules frequency selective? I know that remote control systems use PWM and the pulses are decoded by a...

Are TV IR remote control receiver modules frequency selective? I know that remote control systems use PWM and the pulses are decoded by a microprocessor. What I would like to know is whether the module that functions as the IR photosensor, amplifier and pulse shaper is usually tuned to a particular carrier frequency so that they are not all interchangeable (aside from things like pin-o...


switching regulator with mcu

Started by michael nikolaou in sci.electronics.basics8 years ago 51 replies

Hi to newsgroup I'm making a mcu based device which i want to be very small and low cost The design consumes 100..120 ma @ 3.3V The problem...

Hi to newsgroup I'm making a mcu based device which i want to be very small and low cost The design consumes 100..120 ma @ 3.3V The problem is the installation that requires 12 or 24 volts to operate. I don't want to use a switching regulator to make the voltage drop since its to much circuit involved and also not a zener since its to much heat involved . The mcu has A/D and PWM controll...