fm transmitter coil

zachtheterrible

Active Member

• Apr 27, 2005

• #21

Thats true . . . well, u just blew me out of the water :lol:

 

monkeytree

New Member

• Apr 28, 2005

• #22

(audioguru) @ www.rapidelectronics.co.uk i am unable to get a 30pF capacitor the ones they have are 27pF and 33pF. i am also unable to get the 5-36pF capacitor the ones they have are 5-30pF, 5.2-30pF and 5.5-65pF which should i get?
thank you

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 28, 2005

• #23

monkeytree said:

(audioguru) @ www.rapidelectronics.co.uk i am unable to get a 30pF capacitor the ones they have are 27pF and 33pF. i am also unable to get the 5-36pF capacitor the ones they have are 5-30pF, 5.2-30pF and 5.5-65pF which should i get?
thank you

Click to expand...

30pF isn't a preferred value, you should be able to use either 27pF or 33pF in it's place. As for the preset, either of the two lower value ones will do.

 

audioguru

Well-Known Member

Most Helpful Member

• Apr 28, 2005

• #24

I stole some small ceramic caps from old radios and telephone answering machines. Anywhere near the values I used will work OK.
I was lucky to buy some ultra-miniature ceramic trim-caps, but the normal small plastic ones will be OK.

Try making it with very short wiring. Another guy reported that his didn't work. It looked like this:

 

Attachments

• fm_circuit.jpg

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monkeytree

New Member

• Apr 28, 2005

• #25

im sorry to keep being so anoying
but i cant get LM2931A5.0 and i really dont know what alternative to use
sorry and thank you again.

 

Roboticinfo

New Member

• Apr 28, 2005

• #26

reply

This website sells that component

**broken link removed**

 

audioguru

Well-Known Member

Most Helpful Member

• Apr 29, 2005

• #27

All semiconductor manufacturers make low-dropout 5V positive series regulators.

 

monkeytree

New Member

• Apr 29, 2005

• #28

what current? because my perants wnt let me order from that site

 

audioguru

Well-Known Member

Most Helpful Member

• Apr 29, 2005

• #29

Here are the specs and datasheet. I used an LM2931AZ5.0 and the "Z" is the small transistor package. Its max current is 100mA.
**broken link removed**

 

monkeytree

New Member

• Apr 29, 2005

• #30

100mA fixed voltage regulators – 78L/79L series
Miniature fixed voltage regulators with internal overload, thermal and short circuit protection.
• TO92 plastic case

Click to expand...

this is okay isnt it?

 

audioguru

Well-Known Member

Most Helpful Member

• Apr 29, 2005

• #31

A 78L05 "ordinary" voltage regulator needs at worst case a minimum input of 8V to regulate properly. A 9V battery drops to 6V over its life and would be too low for the "ordinary" regulator.
My "low-dropout" regulator needs at worst case a minimum input of 5.6V to regulate properly so works fine until the battery is dead.

Aren't you in the UK? I checked Farnell and they don't have the one I used.

 

monkeytree

New Member

• Apr 29, 2005

• #32

im not too botherd about battery life but would it still work for a litle while atleast?
last question i promise