Resistor = volts can you help please

[tricku]

I have a few questions as I am very new to this type of thing, thanks also for looking.

I have a model boat that I have made and I need help with the following.

1) I have a servo which I have ripped out the guts and wired it from the motor direct. It runs on a 1.5v battery fine but I need it to work from a 12v battery and know I need a resistor but what one. Can you help.

2) I have 6 - 8 led's in line and not sure again what reistor I would need.

3) If I have a Led that is say upto 6v but want to run it from a 12v battery what reisito do I need for this.

Can I use the same resistor for all three needs

I hope some one can help me and you are welcome to contact me on my email address
richard@tricku.com I am based in Kingston upon Thames, Surrey, England.

0208 549 9234
M: 07974 357 911

Richard Special MMC
Magic Circle Magician and Entertainer.

P.S. No I can not use any magic to make this happen. I'm a magician not god, well not yet anyway

 

[cowana]

1) I have a servo which I have ripped out the guts and wired it from the motor direct. It runs on a 1.5v battery fine but I need it to work from a 12v battery and know I need a resistor but what one. Can you help.

As the current draw of the motor varies, it is not possible to use a fixed resistor. Rather, you need to use a voltage regulator set at 5v (or under) for the motor).

Motor: 6v max
Min load: ~100mA
Therefore resistance somewhere around 60 ohms would protect the motor from damage, but you'll have very, very little torque available.


2) I have 6 - 8 led's in line and not sure again what reistor I would need.

What colour LEDs (this is of great importance - the Vf of LEDs depends on the colour)? Is this off 12v?

3) If I have a Led that is say upto 6v but want to run it from a 12v battery what reisito do I need for this.

A 220 ohm resistor should do the job nicely.

Can I use the same resistor for all three needs?

Probably not.


I'm based locally, so if you want me to send you any of the parts you need (such as the voltage regulator), I can stick them in the post for a few quid .

Andrew

 

[tricku]

Hi Andrew,

Would love to have a chat can you call me in the morning so I can order a few things from you.

Kind Regards
Richard Special MMC
0208 549 9234
07974 357 911

 

[cowana]

I've emailed you.

Andrew