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 Forum: General Discussion   Topic: Nicad Battery Charger with NiMH Batteries.............

Posted: Wed May 16, 2018 1:25 pm 

Replies: 3
Views: 41


At 400mAH, 50mA trickle would be 10mA over.

The AA size NiMH cells I saw at Digikey were 2300mAH and 1900mAH (2.3AH and 1.9 AH). I thought the 400mA in your first post was the max discharge current, not the Amp Hours rating.

 Forum: General Discussion   Topic: Nicad Battery Charger with NiMH Batteries.............

Posted: Wed May 16, 2018 4:28 am 

Replies: 3
Views: 41


What is the mAH rating of the cells? (AKA "C")

spec sheets for two manufacturers and Wikipedia say Trickle charge (no delta temp or delta V) at 0.1 times mAH, or less, is safe. (0.1 x C)

If your charger really is limited to 50mA max, it should be okay.

Cheers,

 Forum: Projects & Kits   Topic: Would this 78SR-5/2-C work as a drop in replacement?

Posted: Mon May 14, 2018 8:20 am 

Replies: 3
Views: 49


You mean across the regulated 5V (to ground) before the display? Yes, but zener knee is not very sharpe. 6.xV or 7.xV would probably be better. Check the curves on the data sheets. You want 5.2V to be definately in the cutoff zone of the zener. (higher would defeat the purpose of using it though!) C...

 Forum: Projects & Kits   Topic: Would this 78SR-5/2-C work as a drop in replacement?

Posted: Fri May 11, 2018 7:55 am 

Replies: 3
Views: 49


Replacing one linear regulator with another linear regulator having higher max current rating solves part of the problem. But, heat (power) generated is the voltage drop across the regulator (not the output voltage) times the current. Increasing the current (even if still under max) requires a bigge...

 Forum: General Discussion   Topic: Typical 0.1 μF bypass capacitor value...

Posted: Fri May 04, 2018 8:06 am 

Replies: 4
Views: 83


Depends. Replacing a 0.1uF ceramic disk capacitor with a 1.0uf ceramic disk capacitor would be better. But, probably over-kill for not much improvement in performance, more expense, and more PCB space. Replacing a 0.0uF ceramic disk capacitor with a 1.0uF electrolytic capacitor could (repeat could) ...

 Forum: General Discussion   Topic: Security light motion sensors in parallel

Posted: Thu Mar 22, 2018 9:04 am 

Replies: 11
Views: 478


sorry too! no downloads here (at my end), so haven't seen the diagram.

 Forum: General Discussion   Topic: Security light motion sensors in parallel

Posted: Thu Mar 22, 2018 7:30 am 

Replies: 11
Views: 478


Didn't say fed from single circuit in post 1.

 Forum: General Discussion   Topic: Security light motion sensors in parallel

Posted: Thu Mar 22, 2018 3:53 am 

Replies: 11
Views: 478


Do NOT connect the red wires (at least not yourself). They are switched AC hot leads. If AC to the detectors happens to come from different phases you'll at least pop a breaker. Even if you "get lucky" with the phases, one detector being on "bright" could damage the other as sghi...

 Forum: Computer Programming   Topic: web outlook mystery ( AKA Hotmail ? )

Posted: Wed Feb 14, 2018 9:01 am 

Replies: 4
Views: 399


Which is it, Outlook or Hotmail? Or, Outlook checking mail on a Hotmail account? Or2, do you mean Outlook.com, domain name for HotMail? Outlook is an e-mail client program by Microsoft (often part of MS Office). Hotmail is a web based e-mail service owned by Microsoft. "Outlook" and "...

 Forum: General Discussion   Topic: Detecting a magnet... from a distance.

Posted: Thu Feb 08, 2018 4:17 pm 

Replies: 23
Views: 1569


In post 1 he said he wanted more posts on the forum.

 Forum: General Discussion   Topic: Detecting a magnet... from a distance.

Posted: Thu Feb 01, 2018 4:17 pm 

Replies: 23
Views: 1569


Quote:
I recall rumor that ...
Not a rumor (that it could be done).

 Forum: General Discussion   Topic: i need some more Unobtainum...

Posted: Tue Jan 23, 2018 7:06 am 

Replies: 15
Views: 852


Quote:
... so i am more than sure it is working ...
No, you are not. You're sure it is transmitting something. Has the carrier drifted outside what the receivers are tuned for? Is the ID code transmitted the correct one for that transmitter/receiver pair? Is the data being transmitted corupt?

 Forum: General Discussion   Topic: i need some more Unobtainum...

Posted: Mon Jan 22, 2018 9:19 am 

Replies: 15
Views: 852


???????????????????????????????? You replaced the receiver, still have a problem, and still say the transmitter is okay? Or did you mean you couldn't find a new receiver to buy? If the first case. the transmiter could be transmiting garbage. Cheers, P.S. A new non -rechargeable battery is 1.55V, so ...

 Forum: General Discussion   Topic: Hammond die cast al case, heat sink?

Posted: Sun Jan 21, 2018 12:37 pm 

Replies: 11
Views: 1035


Can you calculate with Ohm's law? The thermal calculations are about the same. Temperature (degrees C) instead of voltage. Thermal resistance (degrees C per W) instead of Ohms. Power (Watts) instead of current (Amps).

But as you say, it is IMPOSSIBLE without the specs.

Cheers,

 Forum: General Discussion   Topic: Hammond die cast al case, heat sink?

Posted: Mon Jan 15, 2018 4:52 am 

Replies: 11
Views: 1035


The pdf linked to in the original post is the spec sheet for all the cases in the model series. (as in many sizes)

There is no way to tell if a box (unknown) will be a good enough heatsink for a particular project without more info.
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