delabs Circuits

Saturday, September 22, 2007

Mains Stabilty and Supply Regulation

I have problem with my power supply... . The power supply uses LM317 and TIP2955 and the unstable AC net here causes the output to drop sometimes below 5V. The normally output is 13,5V. I like to look at your schematics to imporve my power supply.

I could not download pdf schematics file. Could you send me please?

Mail from WV

See some circuits here ...

You have to ensure at least a min of 15V AC to the Bridge or diodes on transformer. Only if a DC of around min 17V is available at input DC of 13.5 can be managed by this circuit. This circuit will not boost a voltage from a lower value for that you need Switching Boost Supplies.

Use AC Voltage Stabilizers or ServoStabilizers to maintain a stable AC Supply.

WorkBench Dual Power Supply
LM317 - Simple Workbench Dual Power Supply

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.....I like to compare with my schematics from our power supply. We have something very strange.. the backup battery takes over and don't cause a voltage drop when I disconnect power supply from 220V AC lines.. but the backup battery can not anticipate the disturbances in the 220V AC lines and gives a very short power drop at the output..

We have sometimes very short power drops at the output of the power supply.. Do you have any idea what is wrong? The transformer is 16V AC 3A
Reply from WV

You can double the size of filter caps at input. use something like 10,000uF, if you draw 3A a 10000uf across the input rectifier may help. Or you have to use a battery of 12V after the LM317. So that the battery can supply the short outages.
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But that is exactly my problem, we have a large battery after the power supply of 13,5V 5,5Ah, but it doesn't help to avoid the powerdips after the power supply..
Reply from WV

I feel you have a ground loop problem, The wires to the battery seem thin. I feel the potential across a ground wire must be lifting up when mains fluctuates.

The PCB ground plane may be thin or absent, check all ground and supply wires. Make all supply wires and Tracks thick and radiate from a center copper lug reference. Both positive, negative and ground tracks reinforce with lead or copper braids. Use decoupling caps at every stage.

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Sunday, March 25, 2007

Visual Inspection for Quality Control

Wanted a Circuit: "missprinting cartons reject" in production - Message: pls give me help about mention subject.

Mail from SS


You can scan the manufactured objects with a camera connected to computer USB. Then compare the scans got with a reference standard. Apply a tolerance for acceptance or rejection. Based on the quantity of rejections improve process, till faults are within acceptable limits.

The scanned object must be in same position and same angle for proper results. This depend on some guiding system in conveyor to make object position properly.


Inside the Box Winn Hard
Machine-vision system validates barcodes on packages within cartons.

Read This Interesting Article - Inside the Box Winn Hard

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Friday, March 09, 2007

Simple Battery Characterizer

I was reading about some IC's from Maxim/ Dallas saying " Simple battery characterizer" for plotting a charging/ discharging cycles & graphs are available on computer for study I want to plot an extensive data of these batteries.

From MO


This circuit is a battery characterizer that applies a fixed load to a charged NiCad or NiMH cell and measures milliamp-hour capacity as it discharges.

Battery Characterizer: (Electronic circuit added 4/05). Battery Simulator Provides Current Limiting : 08/01/97 EDN Design Ideas / (added 5/03) A ... Battery Tester Electronic Circuits - www.discovercircuits.com.

Keywords: rechargeable AA cell, USB port, Visual Basic program, battery ... AA-Cell Characterizer software, written in Visual Basic, performs the cell ...
Simple Characterization Circuit for Rechargeable AA Cells - Maxim ... - www.maxim-ic.com.

rechargeable AA cell, USB port, Visual Basic program, battery ... AA-Cell Characterizer software, written in Visual Basic, performs the cell ...

Monday, February 12, 2007

Door access controller

I am trying to design a 4 door access controller. I have a complete working board of fingerprint scanner with DSP for fingerprint verification and authentication. I wish to design a microcontroller board which will communicate with this board to trigger the scanning process, store the data in PC and operate 4 relay circuits using the external wiegand relay output of the DSP. thanks in advance

Mail from RU


Have a look at these links

Look thru all the sites you may get ideas.

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Others

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