Re: Any interesting site to learn the basics about rc electronics?
- From: Alex <ad1979@xxxxxxxxxx>
- Date: Sun, 15 Feb 2009 11:39:15 -0800 (PST)
Alex wrote:
3. My Tx also has a small hole at the side that contains a small pin
where I can plug in a round female jack. It says "charge" with a
polarity icon under it. Can I use this to charge 8 rechargeable AA
batteries inside the Tx?
Probably. The manual says nothing about it?
No, I couldn't find anything.
Or can I connect it to use the Tx without batteries?
This might work, depending on the setup of the Tx. However it might
cause radio interference, depending on the quality of the power supply.
Can I use the power adapter for this purpose? It converts 230V AC 50Hz
into 12V DC. I just tried this but with no success. I tried the
polarity switch in both positions. The transmitter appears dead with
no batteries and power cable connected.
Then I noticed the voltage increases to about 7,03V before it
drops to 6,62V and this with nothing connected to it. Explanation?
The cell slowly creeping up in voltage is caused by its chemical
processes delivering a few more electrons slowly and when nothing is
connected to it, or something like a multimeter with a very high
resistance, the voltage will creep up slowly. Connecting the slightest
load will make that drop again.
The first part I understand but that it drops again with the slightest
load was not the case since there was at all times nothing connected
to the bat. I simply measured voltage and then left the battery alone
for 20 sec, measured again and waited 20sec with nothing connected
etc. Voltage was increasing until a peak of around 7.03V before it
dropped again. Nothing was connected.
This is why alkaline battery testers apply a moderate load, as checking
them with a high-R multimeter would still show 1.5V even for pretty
depleted cells.
I didn't know this. So when I want to measure the voltage of an
alkaline battery I should not measure this directly from pole to pole
at the battery because it will always appear to be full?
The battery must have:
- the right voltage
- a low enough inner resistance
- the ability to deliver enough current. This is usually measured in "C"
I.e. 20C means it can deliver 20x the Capacity in mAs as mA.
Or to say it in another way: It can be discharged fully in 1/20th of
an hour without damage.
So that's why RC models need special batteries like NiMH or LiPo
because ordinary alkaline batteries can never develop the same amount
of current due to chemical limitations?
I remember a year ago buying 1.2V AA size NiMH rechargeable batteries
of 2000mAh for my digital camera was a big deal but now they even have
the same batteries at 2700mAh. The technology seems to be continuously
improving. Is that the same for RC model batteries? Will we be able to
fly for 30min instead of 10 with the same size batteries that we have
now? Just wondering.
Thanks for the help, I really appreciate it. "Dr McCoy to the bridge,
there seems to be intelligent life forms out here"
.
- References:
- Prev by Date: Re: mjere sablji
- Next by Date: Re: Any interesting site to learn the basics about rc electronics?
- Previous by thread: Re: Any interesting site to learn the basics about rc electronics?
- Next by thread: Re: Any interesting site to learn the basics about rc electronics?
- Index(es):
Relevant Pages
|
