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You could just add boost converter like the TL496 to a 9v circuit.
Short Wave radios were used a long time ago so their circuits are old.
An old audio amplifier circuit that uses a 3V supply and an 8 ohms speaker will produce only 0.05W of power. As loud as an earphone. When the battery voltage drops to 2V as it is used then there will be no sounds.
If a radio is designed to use a 3V battery today then it will use a modern class-D bridged circuit in a PAM8403 audio amplifier IC. When its battery drops to 2.5V then its output power will be 0.5W in each of its two 4 ohms speakers.
An old audio amplifier circuit that uses a 3V supply and an 8 ohms speaker will produce only 0.05W of power. As loud as an earphone. When the battery voltage drops to 2V as it is used then there will be no sounds.
If a radio is designed to use a 3V battery today then it will use a modern class-D bridged circuit in a PAM8403 audio amplifier IC. When its battery drops to 2.5V then its output power will be 0.5W in each of its two 4 ohms speakers.
Batteries have part numbers. A tiny 186 button cell is 1.5V. The 1.5V cells in a 9V battery are AAA. Then the larger 1.5V cells are AAA, AA, C and D.
You select the chemistry (alkaline?) then their datasheet tells how many mAh they have for their capacity.
If you want a receiver battery to last for a long time then the current used by the radio must be low or the battery must be large.
To use low current then the receiver loudness must be low (earphones).
You select the chemistry (alkaline?) then their datasheet tells how many mAh they have for their capacity.
If you want a receiver battery to last for a long time then the current used by the radio must be low or the battery must be large.
To use low current then the receiver loudness must be low (earphones).
You may have a look at the SI473x chips which operate down to 2 V.
You will need an additional controller chip (microcontroller).
I also stumbled across this chip. No separate controller required.
You will need an additional controller chip (microcontroller).
I also stumbled across this chip. No separate controller required.
I presume you are thinking 9V means you will use a PP9 which have a reputation for not lasting. However a modern alkaline PP9 can last quite well, particularly if your radio uses headphones instead of a power amp and speaker. Alternatively you can buy rechargeable PP9 style batteries but they can be pricey particularity if you need to buy a charger as well. Thirdly you could use 6 x AA or AAA in a battery holder if you are not bothered by the bulk. Then you could use any of the 9V designs.
However, I came across this simple looking receiver which looks nice. It all depends on the performance you want.
http://www.circuitstoday.com/single-transistor-radio
This design is for the medium wave. No details are given on how to construct the tuning coil apart from it being 0.35 mH and being centre tapped. A bit of research on line will tell you how to wind one for the short wave frequencies.
However, I came across this simple looking receiver which looks nice. It all depends on the performance you want.
http://www.circuitstoday.com/single-transistor-radio
This design is for the medium wave. No details are given on how to construct the tuning coil apart from it being 0.35 mH and being centre tapped. A bit of research on line will tell you how to wind one for the short wave frequencies.
From many available in the market :
----> https://www.walmart.com/ip/Kadell-P...MIifntz4_v4wIVlP_jBx0czQ6NEAQYASABEgKxN_D_BwE
----> https://www.walmart.com/ip/Portable...MIifntz4_v4wIVlP_jBx0czQ6NEAQYBCABEgKC5_D_BwE
I have a couple of these available , new in box :
----> https://www.amazon.com/IdeaWorks-FB...=2025&creative=165953&creativeASIN=B00R6TTTBO
----> https://www.walmart.com/ip/Kadell-P...MIifntz4_v4wIVlP_jBx0czQ6NEAQYASABEgKxN_D_BwE
----> https://www.walmart.com/ip/Portable...MIifntz4_v4wIVlP_jBx0czQ6NEAQYBCABEgKC5_D_BwE
I have a couple of these available , new in box :
----> https://www.amazon.com/IdeaWorks-FB...=2025&creative=165953&creativeASIN=B00R6TTTBO
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I will ask again, why it must be 3v?. A pp9 is portable too.
Sometimes a proper explanation of what you are trying to do yields positive responses.
So far in all your posts, is about old transmitters and receivers. Is there a particular reason you choose old technology?.
Sometimes a proper explanation of what you are trying to do yields positive responses.
So far in all your posts, is about old transmitters and receivers. Is there a particular reason you choose old technology?.
I don't get it why you asking this again?
it is perfectly clear to anyone that A celles have longer life and can
deliver more current than 9V batteries.
I see that most of "experts" here like to talk,talk,talk,,,,
without giving real help to one who ask question.
Why is that ?
Old transmitters,receivers ..what is old ?
Or why everything must be digital?
it is perfectly clear to anyone that A celles have longer life and can
deliver more current than 9V batteries.
I see that most of "experts" here like to talk,talk,talk,,,,
without giving real help to one who ask question.
Why is that ?
Old transmitters,receivers ..what is old ?
Or why everything must be digital?
