Technical Radio Test

I have a new Radio that I want to power up on the bench to see how it works before I make the effort of taking old radio out and cutting anything..Can I use a battery charger for a power supply or should I hunt up a battery? Some one was saying a charger is not real DC but half wave AC and may not power the radio properly..I sorta know what he is talking about [small sorta] but thought I'd check..

 

I'd use a battery....for sure.

 

Absolutely, use a battery, either that or a professional type repair power supply.

 

OK will do, Thanks..

 

Some battery chargers (e.g. this one) have a "supply mode" which you could use to power your radio.

 

You can filter out the ripple from a battery charger (this will give you a "buzz" or "whistle" background noise) with a large value capacitor of the right voltage- or if you connect the charger to- you guessed it- a car battery. (even a partially dead one, the battery acts like a big capacitor).

 

i use my jump box, when i need to test things. you could use jumper cables or test leads if you have a car parked near by. i also have a plug with two wires that plug into a cigarette lighter.

 

New, modern radio?
Cheapy? Type?
Make sure none of the loose wires are shorted or touching others or the case before you turn that thing on, could blow out the internal amp.
Could.

Sent from my SM-G955U using The H.A.M.B. mobile app

 

I use the lawn tractor battery for bench testing 12V accessories.

Phil

 

that one would cost more to buy here in the US than several new car batteries!

 

It's nice to see that some products are cheaper (although I wouldn't call this charger "cheap") here in Sweden than in the U.S. In this case it's not so surprising tho, since CTEK is a Swedish company. Good car batteries on the other hand aren't cheap, mainly because of environmental taxes.

 

we can get a new car battery for $50. I wouldn't call it "good", but good enough.

 

Correct. Rectified AC without capacitor/battery to act as a buffer when the voltage output is zero is quite unsuitable to drive electronics such as a radio.

Downside to using capacitors and no active voltage regulation is that the capacitors charge to the peak voltage of the pulsating AC, not the average voltage we normally speak about. For a normal sine wave the peak is square root of 2 (1,414...) of average, meaning a 6V sine wave would charge a capacitor to 6*1,414= 8,5V.
Batteries do not work quite like this, they dampen peaks and stabilizes voltage much better.

Indeed, an old, basic, unregulated 6V charger probably gives 8-9V without load. Add a capacitor to that to filter out the ripple, you could have close to 13V out of it - or 26V out of a 12V charger. Quite possibly enough to kill sensitive electronics such as those you might find in a radio.

 

Cordless tool batteries of correct voltage are a great source to get testing power from. Very light weight and compact.