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|This simple and inexpensive circuit can produce a dual (positive and negative) voltage from a single supply input. It is therefore extremely useful for powering opamp and other circuits that require a dual voltage from a single battery. The circuit will operate at an input voltage from around 5V to 20V and produce a output from +-2.5V to +-10V.|
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|The original circuit appeared in the National Semiconductor Data Books as AN-69 (application note) in Dec. 1972. The circuit is correct as shown, however, the outputs as shown here are slightly different than in AN-69. AN-69 shows the 'positive' from the center (0) to the upper output as V+ with an arrow pointing upwards (from 0) to the upper output. It then shows the 'negative' from the lower output to center (0) as V- with an arrow pointing upwards (from lower) to the center (0).|
|to the previous poster : Imagine a 9v battery. It is connected to the ground of the 9v source. The outputs from this circuit are 4.5v, 0, -4.5v. The potential difference between 4.5 and -4.5 is 9, exactly the same as the battery. As long as you dont earth anything else to the 9v battery's -ve terminal believing its 0v, you will be fine (its actually -4.5v with reference to the 4.5v and 0v outputs). Voltage can be a tricky thing to get your head around. There is no such thing in a circuit run off a battery as 'earth'. Just a difference in voltage potential between the two terminals.|
|Have you ever considered the fact that it is physically impossible for it to work? Look at the -V/2 output, it's connected to the ground|
|you have been a great help to many peoples in career and more especially to me thanks for your good works|
|This circuit can be used to power a small strobe or fluorescent lamp. It will generate over 400 VDC from a 12 VDC, 2.5 A power supply or an auto or marine battery. While size, weight, and efficiency are nothing to write home about - in fact, they are quite pitiful - all components are readily available (even from Radio Shack) and construction is very straightforward. No custom coils or transformers are required. If wired correctly, it will work. Output depends on input voltage. Adjust for your application. With the component values given, it will generate over 400 V from a 12 V supply and charge a 200 uF capacitor to 300 V in under 5 seconds. For your less intense applications, a fluorescent lamp can be powered directly from the secondary (without any other components). This works reasonably well with a F13-T5 or F15-T12 bulb (but don't expect super brightness). Q1 does get quite hot so use a good heat sink. C1 1 uF D2 1N4948 R2 +------||------+ T1 1.2KV PRV 1K 1W | | +-----|>|-----//---+------o + | R1 4.7K, 1W | red ||( blk | +-----//-----+------+ ||( | | yel )||( +_|_ C2 + o----------------------------------+ ||( --- 300 uF | red )||( - | 450 V | +--------------+ ||( | | Q1 | ||( blk | 6 to 12 | |/ C +--------------------+------o - VDC, 2A +----| 2N3055 Stancor P-6134 D1 _|_ | E 117 V Primary (blk-blk) 1N4007 /_ | 6.3 VCT Secondary (red-yel-red) | | - o------------+------+|
|the astable multivibrator is not working. It will be wise and more appropriate to use a driver/pre amplifier to drive the power transistor before feeding it to the transformer.|
|Hi! i find this design very usefull, thanks... i would like to know if there will be a change to increase the ouput voltage to at least ±12 to ±15 volts? What will be the new design?|
|Can you be kind enough to furnish me with a circuit to double the Secondary output voltage of this transformer. I believe that the current in this respect is divided by 2. Regards Ralph|
|Hey! You couldn't possibly be able to tell me how many amps this can handle? I need it so i can create a phase shift oscillator for my op amp, that means i can make a near sine wave to power my inverter!|
|Your site is fantastic I have viewed Your site please can you give me more explanation on the complete circuit of 5KVA inverter and 10KVA Inverter and there circuit board with the automatic changer thanks you|
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