Temperature control for CPU

My name is IS and I am looking for somebody to design and build a simple circuit that controls a small computer fan using either a 120V plugin or a battery using a temperature switch... In other words I would give you the set point and at that temperature it would turn on the fan and when it drops below the set point it turns off the fan.. the temperature would have to be measured using a contact type measuring device like a thermocouple or thermistor.

Mail from IS Brazil

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Go thru these links and visit all pages -

• Temperature Measurement circuits, Thermistors, Sensor circuits
• Temperature Control Circuits - DC
• The encyclopedia of electronic circuits, Volume 6
• Craig's thermostat circuits
• Standard NTC Thermistor Applications - Thermistors
• Two Temperature Controlled Relays
• OMEGA Interchangeable Thermistor Applications
• Industrial motor control By Stephen L. Herman
• Mims Circuit Scrapbook, Volume 2 By Forrest M. Mims

delabs

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PC Sound Card Oscilloscope

Dear DAPJ: I would like to buy a Microphone and either #1. an oscilloscope or #2. sound oscilloscope software. For hobby purposes, I would like to sample different sounds & view the various sound waves studying the amplitudes & frequencies. Do you have a product that would meet these criteria?

Thank you. Respectfully,

Mail from MH - US

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No i dont sell anything. But here are a few suggestions.

Simple solution for only sound - Zelscope buy only software. Test out out, buy if you like it. You need a computer.

Buy a PicoScope or if you want to build one Bitscope

Study also

• 062 Digital Storage Oscilloscope
• Digital Oscilloscope DIY Kit - SparkFun
• µSCOPE A poorman's oscilloscope Ronald Dekker
• Oscilloscope Delphi Program - Sound Card Gary Darby
• Soundcard Oscilloscope by Christian Zeitnitz

delabs

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Power Oscillator Circuit Design

I am trying to find a circuit diagram for a long time, which will give me the o/p Characteristics as 12V, 0.5A & 4000 Hz (or variable frequency). Will you please help me in this regard? I will be very very thankful to you.

Mail from PS IN

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First make an Oscillator and then Power Amplify it.

EDUCYPEDIA - electronics circuits oscillator.

Waveform Generators, Page 1 DiscoverCircuits.com

Power Amplify. Linear Amp is required, Audio Amp in not enough

LM675 Power Operational Amplifier

AN-272: Op Amp Booster Designs

12V, 0.5A & 4000 Hz (or variable frequency) is possible, very high frequencies difficult, for that you have to study RF behavior. Experiment from DC to 1 M Hz, no more with these circuits. 200/300 K Hz if you manage you learn't something. Study pages, learn and try to build it yourself. These links are for learning.

delabs

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I am extremely thankful to you for your precious reply for my mail. I have tried it to complete the circuit as per your suggestion, but the results are not as per the requirements. Here, I tell you the exact situation. Sir, I am working on the efficiency improvement of an alternator. for this reason I need a frequency generator circuit which will give me the o/p characteristics as 12V, 0.5A & variable frequency upto 4000Hz. The signal must be AC sine waveform. It can be applicable to inductive load. The i/p will be simply 230V AC.

Will you please design a circuit for such requirements?

I am in great need of this. Please, I request you to design it. I will be very very thankful to you.

Reply from from PS IN

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For professional service, there will be design charge. Your reply will be posted. Anyone who can design this can comment here.

delabs

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Sci.Electronics.Repair FAQ

Sci.Electronics.Repair FAQ

Sci.Electronics.Repair Frequently Asked Question(s) (or S.E.R FAQ for short) Home Page. This site features Samuel M. Goldwasser's latest and greatest "Notes on the Troubleshooting and Repair of..." series of comprehensive repair guides for consumer electronics equipment and other household devices. There is also a great deal of other information of interest to the electronics hobbyist, experimenter, technician, engineer, and possibly even the dentist and poet. Included are the now quite comprehensive and massive "Sam's Laser FAQ".

• Home and Mirror Site Locations
• On-Line Tech-Tips Databases.
• Sci.Electronics.Repair FAQ
• Technology Resource - Silicon Sam

Sam's Laser FAQ has a great deal of information on a variety of laser and optics related topics including a comprehensive treatment of diode, helium-neon, argon/krypton ion, and CO2 lasers as well as amateur laser construction including numerous examples of truly home-built lasers. Much of this is not available anywhere else either on-line or in print!

Eng-Tips Forums - Electrical and Electronic

Eng-Tips Forums - Electrical and Electronic

These pages will probably help you do a design review of your new circuit or even answer a doubt in your product design. Use the Search.

• Electric power engineering
• Electric motors & motor controls engineering
• Electrical/Electronic engineering other topics
• Circuit Design
• Programmable Logic Controllers (PLC)
• Communication & Signal Processing engineering
• Antenna & Propagation engineering

Eng-Tips Forums