delabs Circuits

Sunday, March 20, 2016

Precision Temperature Control with PID and SSR

I want to make a furnace controller by PID and SSR that can control temperature of the precision of .1 degree.Would you suggest me some controller and SSr that can do this job

from RV

You can find more information here.

Temperature Controllers and Power Switching

You have to use a RTD or IC Sensor for more measurement accuracy. The control accuracy can be obtained by a Auto Tune PID controller and Thermally Optimizing the System or Equipment. That means Heat Transfer, Sensor Position, Sensor Size, Heater Type, Fans, Thermal Inertia and many things that can be studied by experimenting or learn it from the field engineers.

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Notes -

If the system is a small chemical bath you need to stir with motors for convection, if it is an Oven a Fan for air circulation may be required. The control signal from the controller can be a PWM pulse train or 4-20mA depending on what you drive. A pulse train for a DC SSR or 4-20mA for a DC Drive. The Controlled Actuator may be a Heater, Fan or Compressor.

If it is a temperature of 20 deg C, that needs to be controlled and the product is for the global market. Then you need a heater to bring a temperature to 20 deg in Alaska, but in Congo a 20 deg can only be obtained by Cooling the system.

Precision Temperature Control with PID and SSR

A Block Diagram showing how a Temperature Controller and SSR is used in Control. For Furnace more SSRs and more Heaters have to be used.

Create SSR banks in the control panel and many Heaters well distributed in the heating area. Use a PID or Proportional controller with On/Off output for SSR control.

For very Large Systems use a Booster Heater bank and Separate Controller only for the Start Up.

See my Temperature Measurement and Control you will understand better.

Friday, March 18, 2016

Hypersonic Speakers - Acoustic Heterodyning

i have been searching for any technical help regarding my project, hypersonic speakers,but my efforts were in vain. hypersonic speakers are interesting to work upon. kindly guide if if you have any knowledge regarding the topic. Mail from GA


This looks like something from the "Believe it or not", I cannot understand it well, but logging it here. - delabs

What Are Some Woody Norris Successes?

Hypersonic Speakers - Acoustic Heterodyning

Hypersonic Sound: Sound From Thin Air - Mix two signals in a nonlinear medium and you'll end up with four - two at the original frequencies....

"Acoustic heterodyning can be created by a single transducer or by a pair of transducers. A single transducer would be fed a signal at a "carrier frequency" and a second signal that would provide the desired (audible) difference frequencies when mixed with the carrier. If a pair of transducers were used, one would operate at the carrier frequency and the second at a frequency required to produce the desired output.

If the carrier frequency of the transducer were 200 kHz, an upward swing of 20 kHz - or just 10 percent - would cover the entire audio range. In theory, this should result in a response that is virtually flat across the audio range - something that no speaker"

Hypersonic Sound speakers are like Invisible headphones.

Sound technology turns the way you hear on its ear - Woody Norris, inventor of ultrasound technology,

Acoustical Society of America Lay Paper on Hypersonic Sound: -

HyperSonic Sound HSS from American Technology Corporation employs ultrasonics to create audible sound in the air. It works by using harmless ultrasonic tones that we can't hear

More from Woody Norris - HyperSonic Sound. speaker

"With conventional speakers, the sound is projected by moving the air containing the sound waves against a cone moving back and forth inside the box. But with Woody's speakers, it's a process that happens in the air itself. Sound is beamed at the wall and it comes off the wall where it is imbedded on top of the ultrasound. A process that happens in the air unimbeds it, or demodulates the two, so in essence, the room in which you are using the speakers is, itself, the speaker box. "

 Meet Woody Norris

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Thanks for your reply for hypersonic speakers , but sir i am unable to have any positive feed backs as far as its making is concerned, i have contacted hypersonic industries also in this context, but they want me to buy a unit. i will see what i can do. thank you once again for your help.

Reply from GA

I dont know if this idea is good for college projects, but you can buy a Hypersonic Speaker and demonstrate an application in automation.

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Saturday, March 12, 2016

Low Cost Simple CFL lamp

my earlier email ,went unanswered.....  i need some circuit whiz to design a -----Low Cost / Simple discrete component (may include 555 IC ,but no Custom Ballast ICs..)  CIRCUIT----to light up a 7 watt 4 pin, CFL from a 6 volt 4 AH battery +220 volt mains+3 watt Solar Panel

the idea is to make available, reliable lanterns as product, or as a SKD / CKD KIT form, to enable local assembly for poor

mail from SRM



IRPLCFL2 design has schematic and BOM. 

IRPLCFL2 design has schematic and BOM.

The CFL-2 is an electronic ballast design for driving a 42 watt compact fluorescent lamp from a
120 or 230 volt AC line. The circuit was designed using the IR2156 Ballast Driver IC. The main
features of the circuit are programmable frequency, preheat time, over-current threshold and
dead time.

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