Help needing smallest 240v to 9v transformer

Hi I am interested in making my own 240v double adapter spy bug like the one found here:

formatting link

but the price is too much for me to afford, so I would like to make my own. Would the power it needs have some sort of transformer in it?

I have a small bug I made from talking electronics that uses a 9v battery I might be able to squeeze it into an adapter most likely I'll have to customize it.

Does anyone here have any ideas how I would go about making one or any schematics they could offer to make one as this sort of thing is new to me.

Thanks all

GK

Reply to
Gabriel Knight
Loading thread data ...

"Gabriel Knight"

formatting link

** The unit described almost certainly use tiny SMD components so it fits in the space available. The circuit is very likely powered directly from the AC supply - which make it electrically dangerous.

But MOST IMPORTANTLY - using such a device to secretly listen to conversations is a breach of the criminal law anywhere in Australia or most places.

Eg:

formatting link

.... Phil

Reply to
Phil Allison

formatting link

Ok take the for example the voyager MKII and sort out a capacitor derived supply

it will have essentially constant current requirements so should suit the capacitor supply, you're going to need a Y2 rated capacitor else you're building a fire bomb... (I've not read Phil's reply yet, but take his warnings seriously too)

take current measurements from your bug on different supply voltages, eg: 10.5 and 7.5 if the current consumption varies like a resistor it should work fine with an unregulated capacitor supply s long as the capacitor supply is within range, else it's going to need a zener.

formatting link
this one uses an X2 capacitor and a fuse, Y2 is better as they don't fail short-circuit, so if it does fail the bug circuit won't get cooked.

C1 will have to be sized to supply the correct current for your bug

everything right of the zener diode can be replaced with the bug. use a 10V zener. R2 seems larger than is needed it need only be about 10 times ESR of C2

See how it goes, you might get a lot of hum on the transmission. if you do better supply filtering will be needed, perhaps adding a capacitance multiplier stage will be enough.

For experimenting with circuits like this one you really need a mains isolating transformer, here's a cheap way to make a small one.

formatting link

--
?? 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net
Reply to
Jasen Betts

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.