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Tuesday, May 28, 2019

CJC or Cold Juction Compensation

About a month agoo I asked a few explanation on blind controller circuit design, up now i did focused on mechanical parts of my rubber press and now these are ready, i turned myself to the controller :

Qestions came up as I tried to duplicate part of your circuit design on a bread board and could not get a significant reading on DMM.

Why value of TH1 is 5 ohm in this circuit other circuits you design it is mostly 12 ohm ?

I used document DACT0006.PDF to make TH1 and re-calculate values of resistors involved around OP07 for gain and R26 using formula you gives. R26 : 330K ? to not induce anyone error i won't replicate here these calcul, but could you confirm me this value ? (sorry for this one I know it is unpleasant : think I'm lost... )

Mail From SY

Another Method using a Copper Resistor

If wires of two dissimilar metals are joined at both the ends and the junction formed at one of the ends, is heated more than the other junction, a current flows in the circuit due to Seebeck thermal emf. This effect is used in thermocouple temperature sensors.

Thermocouple Temperature DPM - DMM

Thermocouple Temperature DPM - DMM

The Peltier effect is the converse of above Seebeck effect, which means that if a current is forced through junctions of dissimilar metals, the junction will generate heat or absorb heat (cooling) depending on direction of the applied emf. This effect is used to make portable and small refrigerators.


What is the range i should use for DMM for this blind proportional circuit ? what should be the reading ?

Iideal for my purpose will be 1mV per degre Celcius as cheap panel meters range 0- 200mV

One of LM324 operational amplifier output is connected to ground... which is separate from VDD, could you explain me more?

I 'm making now the box that will contain the circuit and support the press itself. When I get over this stage i will make pictures, is 100Kb suitable size to send you ?

Mail From SY

Radar using Laser - Detectors

Radar using laser and microcontroller will u pls help me and provide me the necessary info.

Mail from  VV

Here are some pages in the web that may be useful in your study ...

Integrated electronic and optoelectronic circuits and devices -  for pulsed time-of-flight laser rangefinding

The main focus of this work concerned with the development of integrated electronic and optoelectronic circuits and devices for pulsed time-of-flight laser rangefinding is on the construction of the receiver channel, system level integration aimed at realisation of the laser radar module and in integration of all the receiver functions of laser radar on one chip.

Unusual Radar Detector

This unique anchient design uses a chopper amplifier - The microwave diodes are chopper-gated by a multivibrator so the RF signal level can be detected by an audio frequency amplifier.

 Laser Radar for Vehicle Speed

Laser Radar for Vehicle Speed

Abstract In this research work, new exploration of a pulse laser radar system is presented with two splitted parallel laser beams for the measurement of precise velocity of moving vehicles along with their contours and ranging distances. The emission of optical pulses is eye-safe, and hence the radar can be classified as a class-1 laser system.

Thursday, May 23, 2019

2.5 GHz Frequency counter

"Imagine you have a radio receiver and you wish to display the receiving frequency. As you know the oscillator in a radio receiver works 455 kHz or 10.7 MHz above the receiving frequency. The 455 kHz and 10.7 MHz difference is called IF (Intermediate Frequency)."

2.5 GHz Frequency counter

A Google talk around 2006 with another electronic enthusiast

davidhvm (3:36:51 PM): Hello, i assembled de prototype and work fine
davidhvm (3:37:24 PM): anyway i add a push button to Set/Reset to 00 the counter
davidhvm (3:37:39 PM): thanks a lot again
davidhvm (3:38:13 PM): check this 2.5 GHz Frequency counter
davidhvm (3:39:07 PM): i'm looking for some apps for counters and i
found a lot o pages with very usefull
davidhvm (3:39:44 PM): circuits of course with PICs (Microchip or Atmel)
davidhvm (3:39:47 PM): Bye
delabs (3:44:58 PM): hello david
davidhvm (3:45:37 PM): hi all work fine
delabs (3:45:48 PM): great
davidhvm (3:46:40 PM): are amazing these projects
davidhvm (3:47:15 PM): ok thanks may be for long time
delabs (3:47:30 PM): fine
davidhvm (3:47:41 PM): i'm at middle of my carrer