How can i change voltage??

[radioman24]

I have 3 7 volt tweey bird noise toy's and they are all 7 volt toys how can i lower voltage from a 9 volt battery to give them the right voltage? all i have in my city to get parts from is a radio shack so please keep that in mind to,lol

 

[fnkycoldmedina]

who told you they are 7volt?they are 9 volt toys ,they are made for d104`s and d104`s are 9 volt.
if you want to vary the voltage just hook a potentiometer inline with the power wire and you can slow it down and speed it up .use an old rf gain knob or something similar.

 

[MisterFatty]

who told you they are 7volt?they are 9 volt toys ,they are made for d104`s and d104`s are 9 volt.
if you want to vary the voltage just hook a potentiometer inline with the power wire and you can slow it down and speed it up .use an old rf gain knob or something similar.

Actually your mistaken, DJ Electronics made them for both 7 Volt, and 9 Volt, essentially the same except for value of a couple resistors. They tend to buzz with incorrect voltage, and due to age they could even require less than 7 volts to oscillate properly.

 

[radioman24]

Yeah i got these from misterfatty they are 7 volts and i wanna lower the voltage from 9 to 7 volts what parts does radio shack sell that i can get to do this???

 

[MisterFatty]

I'll see what I have lying around, maybe I can make you something up.......

 

[radioman24]

okay cool

 

[Bionic Chicken]

Hmmmmm, somewhere around a 1K resistor ought to drop the voltage enough.

 

[HiDef]

You can't use a pot or dropping resistor and still get decent voltage regulation if there is any current draw.

Use (3) 1N4003 or similar diodes in series. Each will drop about .6 volts from the source and allow good regulation.

 

[Oldtimer]

You say they are 7 volts and ya want to drop from 9 volts to 7. Am I missing something here?

 

[MisterFatty]

You say they are 7 volts and ya want to drop from 9 volts to 7. Am I missing something here?

These particular tweeties are intended for a 7 volt supply voltage, much like the older TR-175 powered mics supplied, rather then 9 volts.

Not sure where the question lies....

 

[sp5it]

6.8V zener diode with resistor would be the best and simplest choice.
Mike

 

[HiDef]

A Zener would work but you need to know the exact current draw of the 7 volt device as well as the dynamic current draw. 3 diodes in series with the power lead don't care about the dynamic draw until it exceeds their rating.