Hello there everybody!!

I saw a circuit that used 555 timer to charge a 9v Nicd cell. What are the changes I have to make if I want to charge a 2.4v battery?? Or is it fake-for 555 timer is a timer/switch not a charger.

 

It does not seem to work............

 

Alright, I will now make it and test it myself.

 

There are no component values on the schematic. You would have to change the voltage at pin 2. It might be that the pot, P2, has enough range already.

It sounds like you are thinking of charging two NiMH cells in series. Be careful not to over-charge them. You might want to read up on how to change an NiMH cell before trying to do so.

http://www.powerstream.com/NiMH.htm

 

The value of the components are as follows:
P1 = 50K
P2 = 50K
R1 = 820R
R2 = 820R
R3 = 1K
R4 = 10K
R5 = 10K
R6 = 100R
D1 = 4.7V Zener
D2 = 1N4001
D4 = 1N4148
D5 = B40C1500 Diode Bridge
C1 = 220uF - 25V
Q1 = BC547B
IC = 555
B1 = 9V Ni-Cad Battery

 

so, is it possible........

 

so whats the answer??

 

I would have used some of the commercial charger chips. As those take better care of your battery.

 

Thanks!!!!

OK, I have some problem but I cant start a new tread. My thread was this:

"Hello there everyone!!!

I was thinking of making a FM(or AM) radio receiver. I want it to be tune-able. However, I have nothing(at the moment) apart from a 2N2222 and a BC108. Can any of these help to make the radio receiver?? I dont want it to be so much loud(only so that I can listen to it using earphones). I dont have any op-amp at the moment. Is that after-all possible with only transistors, variable cap, a coil of wire and some resistors and diodes??

Thanks in advance for your assistance."

 

The answer is your circuit is wrong on pins 3 and 6, see this one.

http://lh5.ggpht.com/-pAqF4CfAPfs/U...h/nicd-charger-circuit-diagram%255B7%255D.gif

to alter the battery level change the reference voltage on pin 5 to 1.5V and fine adjust it with the pot on pins 2,6

 

I'm writing it here cause I'm unable to start a new thread.

I have an old MP4(JXD) that I want to fix now. I have done everything except the power supply. Instead of Li-Po that was inside it, I want to use disposable batteries. It had 1 3.6v so I'm planning to connect 3-1.5v in series. I tried brand new zinc-carbons but it failed to keep it on for more than 37 seconds literally! I had to plug it into the charger for half a second and then it worked for another 10 seconds. Is it the problem of my MP4 or the batteries? The battery holders are also kinda rusted. Is there anyone out there who can help me out? I thank you for at least reading it.

 

Hey, it works for quite a long time if I connect 4 batts in series. I did not see how long but it played 3 songs without problems.

 

However, another problem has arrived!!

After listening to half a song today, I noticed the joint of the power supply wires to the circuit board really hot. Is this because I have used wood wax and not solder to solder them? I cant get a soldering iron at hand. My father will never let me go out and cant expect him to buy it. Anyways, my parents dont know about it. Is wood-wax some kind if poor conductor? If it is, then it must be shorted. Can you tell me a way to stick wires on breadboard without a soldering iron. Sorry, I cant buy one

 

I'm not recommending it as a solution, but there is such a thing as conductive glue. Figuring out how to get access to a soldering iron would be a better strategy. There are also wire wrap techniques you might look into.

 

Thank you very much for answering!!!

That's what I need-a conductive glue. I will definitely try to get a soldering iron from a friend secretly, but this shall be a backup I believe. I was wondering for quite a long if any glue can conduct electricity. Now if the conducting glue really exists, then I have a hope

 

But no stores have the conductive glue.

I have fixed the problem but another has arrived!!

An IC gets hot! The heat travels along the circuit board and warms the wax which makes it expand and disconnects the wires. I think I shall use a heat sink. But I dont have one

If I stick a thick long piece of aluminium foil on the IC, will the heat pass through the foil instead if the PCB?? The foil piece will be around 5 times longer than the IC.

 

You should start a new thread and show where you are now with the schematic and a picture of your build. It's too hard to speculate without details. A music player should not be getting hot.

 

Sorry, I cant start a new thread. It says- Server error, and that it might be down for maintenance. I will post picture as soon as I can. Thanks.

 

Oh, forget it.

 

Sorry, I cant start a new thread. It says- Server error, and that it might be down for maintenance. I will post picture as soon as I can. Thanks.

Try using a shorter title. Happens to me sometimes