Q Bytes World

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Problem Statement:

My application requires a 2A or 3A +/- monitor.  The ACS712-05B is very limited on it range for what I need:

• 05B = 0.185V / 1A
• 20A = 0.100V / 1A
• 30A = 0.066V / 1A

 

The quiescent is 2.5V, so the 05B @ 5A will be:

• 2.5V+(0.185V *5) = 3.425V Max
• 2.5V-(0.185V *5) = 1.575V Min

3.15 volts are not used, that is a lot of waist for my project.

 

Solution:

I will amplify the output:

• For 2A MAX = 0.185V/1A to 1.250V/1A (gain of 6.8x)
  • @ 1A = 3.750V (instead of 2.685V)
  • @ 2A = 5.00V (instead of 2.870V)
• For 3A MAX = 0.185V/1A to 0.833V/1A (gain of 4.5x)
  • @ 1A = 3.333V (instead of 2.685V)
  • @ 2A = 4.166V (instead of 2.870V)
  • @3A = 4.999V (instead of 3.055V)

 

A map will be used in the Arduino code to display the actual Amp value:

• 2A = map(0,1023,-2.00,2.00)
• 3A = map(0,1023,-3.00,3.00)

 

I searched the internet for a common solution, the below is close and I will update the values to expand the range.

As drawn, the gain is  3.3X.  Add a 10K (10 turn) resistor between the 100K to be able to zero out the value (This can also be accomplished in code).

Here are the values I need:

• 2A
  • R3 =6.8K
• 3A
  • R3=4.5K

R1 and R2 can be as low as 1K and still consume only 2.50mA (12.5 mW).  (Need to change the 10 turn resistor to 100 ohms).

I will use a LM741 instead of the LM321.

 

 

Conclusion:

Need to build and prove this solution has much better resolution.

 

Reference:

http://www.theorycircuit.com/hall-effect-current-sensor-circuit/

https://www.youtube.com/watch?v=RZmGt3-HVlw

https://www.youtube.com/watch?v=DVp9k3xu9IQ

https://www.engineersgarage.com/arduino/acs712-current-sensor-with-arduino/

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Problem Statement:

Solution:

Conclusion:

Reference:

Radio_Shack_-_Engineer’s_Mini-Notebook_-_Basic_Semiconductor_Circuits.pdf

https://www.zpag.net/Electroniques/Kit/Radio_Shack_-_Engineer%27s_Mini-Notebook_-_Formulas_Tables_Basic_Circuits_.pdf

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Problem Statement:

Need to understand the surface mount chip size to understand what I can solder

 

Solution:

Find some reference data

 

 

Conclusion:

I should stick with 1206 mm and bigger

 

Reference:

https://en.wikipedia.org/wiki/Surface-mount_technology

 

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Problem Statement:

Need to know if:

• the ATX is plugged in
• turned on

Solution:

 

Conclusion:

 

Reference:

https://www.wikihow.com/Use-an-Old-ATX-Power-Supply-As-a-Lab-Power-Supply-Without-Modification

 

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_1

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_2

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_3

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_4

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_5

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_6

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_7

https://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_8

Constant Current Load – fritzing.pdf (2.85 mb)

ConstantCurrent.rar (1.27 mb)

http://www.robotpark.com/image/data/PRO/91457/GY_271_ELECTRONIC_COMPASS.pdf

GY_271_ELECTRONIC_COMPASS.pdf (625.55 kb)

Lab Dual 3A PS.PDF (73.71 kb)

Power Kits.pdf (690.66 kb)