Techniques... Making a Dual Supply from a Single Supply

[Thunderchild]

hehe electricity yes some places out in the sticks get their water from a suface run mains pipe and some houses just have wells most people buy bottled water to drink anyway. anyhow in many respects I consider southern Italy a third world country especially mentality wise. oh they have electronics fairs but they seem to be top secret I have never seen any advertised

 

[audioguru]

anyhow in many respects I consider southern Italy a third world country especially mentality wise.

Are you in jail in Sicilia? No wonder you can't get electronic parts.

 

[Hero999]

Even a 555 timer can be used to generate a negitive power supply, both cheap and readily available!
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[danesh]

simple way

Because you want to supply opamps it seems that you need not a lot of current.
Use may a simple square wave oscillator ( like a 4093 or 7414 or 40106 schmitt gate with a resistor in feedback from output of the gate to input and a Cap from the input to GND) to drive a Diode-capacitor ladder voltage pump/doubler/inverter to generate any positive or negative voltage.

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[Ayne]

Thanks.....

Thanks u HERO999
I think it is the good solution for me cuz it is easy and cheap also and can provide +-12volts...

Again Thanks all.

 

[Blueteeth]

That 555 timer circuit won't produce -12v from +12v, more like ~-10.8V because of the voltage drop of the diodes. It'll still work fine for opamps though. You could use one 555 timer circuit to make 9.4V (a booster circuit) and then another to make -9V.

Just thought I'd mention it

Blueteeth

 

[Hero999]

Yes, but if you read the text it does say that the output is 12V assuming the supply is 13.8V

If you only want a really low current supply then use a CMOS 555 with Schottky diodes for a lower voltage drop.

 

[Thunderchild]

Are you in jail in Sicilia? No wonder you can't get electronic parts.

hehe no I am in a mentally underdeveloped place call Alberobello in Puglia, check out my site if you want to see some of it, they are great at having their rights trodden on here.

 

[willy1usa]

Parts Availability

I get a lot of my voltage regulators and even transistors from my local TV repairman's junk ben. Junk computer monitors can also be a good source.

 

[Thunderchild]

hm I did come up with a circuit for making a neg and pos from a single, but never fully tested it just the principle

 

[Nigel Goodwin]

hehe no I am in a mentally underdeveloped place call Alberobello in Puglia.

So why does your location say "UK"?.

 

[Thunderchild]

I moved ! didn't i say I was getting fed up with living in a 3rd world country ? they can't even keep a goverment for its full term

 

[audioguru]

Hi Thunderchild,
Welcome to civilization.

 

[Thunderchild]

thank you not that I'm too impressed with what the UK has become but at least I can go online and buy anything I want and expect some minimum rights at work (although agency's seem to be more about ripping you off but never mind)

 

[shokjok]

Don't North American distributors ship worldwide? If that is true, then "cannot get parts in this country" can't be justified, unless the country is embargoed. Using two identical power resistors tied to the supply lines to establish a reference ground to feed an op amp should give you a reference ground.

 

[eng1]

thank you not that I'm too impressed with what the UK has become but at least I can go online and buy anything I want

If I had seen this post earlier, I could have suggested some web sites where you can order electronic parts online in Italy. It works just the same as in UK or France or USA, etc. I always buy from Distrelec, RS and Farnell (Farnell sells only to VAT registered users). You place an order and you receive it on the next day, no matter if you live in a big town or in a small village.
By the way, I went and visited Alberobello and I liked it very much. It is an UNESCO World Heritage Centre IIRC and people were very kind with me.

 

[Nigel Goodwin]

hm yea but all I can to is toter down to my local tv repairer and ask him to order me stuff. now he has like 10 suppliers and yes start to wounder why does one need ten suppliers for the same stuff ? I have no access to internet buying as I have no debit/credit card and frankly I find absurd that I can hardly order stuff. I phone a man up he goes and looks on his computer and tells me he can't get me IC "x" or any replacement I mean are we joking. do you know how many projects I have just tossed to the wind cause I knew I would never get the parts ?

That's your fault, not the systems - get yourself a credit or debit card - this isn't the 19th century you know!.

You're in the UK, component availability is extremely good, second only to the USA - and the post is probably even better here.

 

[ericgibbs]

thank you not that I'm too impressed with what the UK has become but at least I can go online and buy anything I want and expect some minimum rights at work (although agency's seem to be more about ripping you off but never mind)

hi TC,
If you phone the accounts dept at CPC in Preston, they will most likely open a standard invoicing account. 08701 21 43 47
CPC | CPC - Over 100, 000 products from one of the worlds leading distributors of electronic and related products.
Order by phone or fax for next day delivery, with monthly billing.

On request you can get a catalog.

Farnell own CPC,,, also Farnell will supply components ordered online using a credit card, minimum order value £20GBP, next day free delivery.

 

[jbrock20]

Why not use 2 9v batteries and be done with it? or are they not available?

 

[Thunderchild]

By the way, I went and visited Alberobello and I liked it very much. It is an UNESCO World Heritage Centre IIRC and people were very kind with me.

you were 1) a tourist 2) an Italian (at least I guess from your location), I did live there for 15 years so I sort of know what I'm talking about. I would never live there again unless totaly financially indipendant. They are a unesco site ? so what ? that does not change the attitude of the people that live there. yes it is a vcery beautiful place it is spoilt by the people that live there and run it, it could be made much more interesting and more organised. than a bunch of private shops that argue constantly about their "boundries" and technics used to get people into shops who are made to feel so uncomfortable they hardly buy anything. Coaches come to the town spend a couple of hours there and go they don't even stop in a local restaurant and it is "hoped" that they at least bought some souveniers.