I'm looking for a circuit I can use to power a 2-way radio from a cigarette lighter.
I have seen many options but I was hoping someone could supply a diagram and component values to use.
I would like some sort of protection to prevent over voltages or over current to the radio.

This would actually be used in a tractor, so there are times where the engine will run high and *could* generate more than 12v.

 

You could use a 6V regulator (LM7806, LM317, etc). If the device will operate down to 4.5-5.5V, you could use a car phone charger.

If you're concerned about current limiting, use an in-line fuse. For over voltage protection, you could use a TVS diode.

 

AFAIK there is no such thing as an AAAA battery. If you meant AA or AAA then a 6V regulator is what you need. How much current does the radio draw when you key the mike? How much power does the transmitter have? The reason this is important is that a linear regulator will get much hotter in the transmit position than in the receive position. Is it possible the manufacturer of the radio already has something you can use. As an alternative you might be able to use a +6V lantern battery which will give you long life and a stable power source.

 

I'm looking for a circuit I can use to power a 2-way radio from a cigarette lighter.
I have seen many options but I was hoping someone could supply a diagram and component values to use.
I would like some sort of protection to prevent over voltages or over current to the radio.

This would actually be used in a tractor, so there are times where the engine will run high and *could* generate more than 12v.

Chances are; the parts would cost more than just buying one.

You can probably adjust a car USB charger for the voltage you need, but I have seen car type PSUs with switcheable output voltage. They used to be linear like an LM317, but I have a proper SMPSU type. So I know they do exist.

 

AFAIK there is no such thing as an AAAA battery. I

https://www.amazon.com/aaaa-batteries/s?ie=UTF8&page=1&rh=i:aps,k:aaaa batteries

We use them in led penlights

 

https://www.amazon.com/aaaa-batteries/s?ie=UTF8&page=1&rh=i:aps,k:aaaa batteries

We use them in led penlights

Wouldn't have gone so far as saying "no such thing" - but I can't remember having seen one before.

 

Wouldn't have gone so far as saying "no such thing" - but I can't remember having seen one before.

So I'm like a 3 year old; if I haven't seen it, it doesn't exist.

 

AFAIK there is no such thing as an AAAA battery. If you meant AA or AAA then a 6V regulator is what you need.

I took 4aaa to be a novice trying to say 4 AAA batteries...

 

I took 4aaa to be a novice trying to say 4 AAA batteries...

I did preface my remark with AFAIK (As Far As I Know) which provides some measure of cover from verbal abuse.

 

I did preface my remark with AFAIK (As Far As I Know) which provides some measure of cover from verbal abuse.

Our field demands attention to detail. Wrong capitalization or word choice can be extremely misleading.

I still cringe when I see incorrect capitalization. But, until recently, I thought the abbreviation for kilo was K; I still don't "like" using k, but do it to avoid verbal abuse...

 

I'm looking for a circuit I can use to power a 2-way radio from a cigarette lighter.
I have seen many options but I was hoping someone could supply a diagram and component values to use.
I would like some sort of protection to prevent over voltages or over current to the radio.

This would actually be used in a tractor, so there are times where the engine will run high and *could* generate more than 12v.

Depending on the peak current you need and for how long (probably not very much for very long on a AAAA battery) you could probably get by with nothing more than a 5 volt regulator IC and 1 -2 diodes on its ground pin in a forward biased configuration to push the 5 volt regulator up far enough off the ground referance to get ~ 6 volts. Given the likely low current demands required more than likely a naked TO-220 case regulator IC would do fine with nothing more than a few tens to few hundreds of uF capacitor on the input and output leads between them and the raised ground pin connection point.

 

Excuse the interruption to the very enlightening conversation, but the question seems to be that of how to get six volts from the tractor's electrical system.

@hawk7890 do you know how many amps or millamps your radio requires?

 

If you need one and can't find one locally most 9v batteries are made up of 6 of them in series, Some however have the flat, rectangular cells.

 

If you need one and can't find one locally most 9v batteries are made up of 6 of them in series, Some however have the flat, rectangular cells.View attachment 132177

Most alkaline PP3 are like the picture, most nickel chemistry type use steel jacket rectangular cells - I've seen a few that had mixed size button cells (probably why I found them in recycling).