# 12V DC to 120V AC IMPORTANT!!

Discussion in 'The Projects Forum' started by badrove, Apr 4, 2008.

Mar 18, 2008
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Hello,

I am loking for a circuitry to generate an alternatif signal (about 120 volts AC) but i have just a 12VDC alimentation.

the output frequency should be 100KHz.

Thanks for you

2. ### vel New Member

Apr 4, 2008
3
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pls give circuit

3. ### Søren Senior Member

Sep 2, 2006
472
30
Hi,

Usually I have this effect on women only

Please don't mark your post with "IMPORTANT", that only makes people NOT wanna answer. Any post is important to one who needs an answer, but not really very important to the ones able to give the answer.

Personally, I have a tendency to filter out such posts as well, but a quick answer would be: "Hook up a 555 to a ferrite transformer wound for the purpose".

(See, even unintentional flattery gets you somewhere )

4. ### beenthere Retired Moderator

Apr 20, 2004
15,808
295
Are you trying to make an inverter to drive a load, or do you simply need a circuit for demonstration?

Jul 17, 2007
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6. ### Wendy Moderator

Mar 24, 2008
21,714
3,000
Here is how I would do it...

I have never built this circuit. There may be traps or problems I haven't anticipated, which is why prototypes are built.

Unless we are talking a light load, the transistors will need heat sinked. This circuit should put out a substantial amount of current, so normal safety precautions should be take for high voltages.

7. ### scubasteve_911 Senior Member

Dec 27, 2007
1,202
1
You're going to have a hard time making a 100KHz 120Vac signal with any sort of power capability. What output power or current do you need?

Steve

8. ### SgtWookie Expert

Jul 17, 2007
22,201
1,807
Interesting circuit, Bill.

Just one thing - I recently was reading about a circuit similar to yours; a fellow tried to make the circuit more simple by eliminating the base resistors from the transistors forming the H-bridge; it didn't work after that.
[eta] Found the link to that similar circuit: http://www.solarbotics.net/library/circuits/driver_4varHbridge.html

A wild guess (actually, 12v/100mA, half of the current capacity of a bipolar 555) tells me that a minimum of 120 Ohms is needed on the base of each transistor.

Mar 18, 2008
12
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hi,

i need a low current, about 20mA or less

10. ### DC_Kid AAC Fanatic!

Feb 25, 2008
794
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are you sure 100kHz? why 100kHz? stun gun? what is it for?

11. ### Wendy Moderator

Mar 24, 2008
21,714
3,000

There is one big difference between circuits, the one I drew is an emitter follower design, no resistors needed.