Bridge Rectifier
I received another message from Dan, this time asking about power supplies:
Subject: Frustrated with power converters
So, the past month or 2 I’ve been trying to figure out how different types of AC to DC power supplies work, since i have a few audio/video receivers that im trying to install PC fans inside that require that type of power.
The problem is that I don’t have any power converters that are less than 18 volt DC. I’ve been researching capacitors, different types of diodes and ways to hook them up but I cant seem to lower the voltage. I’ve tried a few different ways to hook a resistor up to it and sometimes the resistor starts smoking or doesn’t change much of anything. im just really annoyed with spending many hours on this simple project. I’d hate to ask you to explain multiple electronic parts since you’re probably very busy so instead could you give me a short answer to this?
I’ve been to over 50 Google websites and cant find anything on YouTube that I understand.
So it sounds like Dan has a situation where AC to DC has been converted, but he DC is too high to use with a 12V fan. The quickest solution is to find an AC fan (they do exist, but they can be noisy, and overkill for this kind of situation). So instead let’s look at the alternatives.
Let’s say that Dan has 18V coming from the Power Supply and he needs 12V to drive a quiet PC fan.
Voltage Regulators
Where you require a large amount of current, using a resistor/potential divider is not always the best idea, as the current levels causing heating/smoking – and that’s usually a bad thing. An alternative is to use a voltage regulator – this does the same thing, dissipates the excess voltage as heat, but does it in a more controlled way and lets you attach a heat sink to it. You need to work out the current required by the motor driving the fan, then multiply this by the voltage drop. So if you are trying to drop 18v to 12v and your fan needs 1/4 amp – this would be (18-12) * 1/4 = 1.5 Watts. (Watts being power and equal to volts x amps). The hookup is simple – 3 legs: input voltage, gnd and output voltage.
So your regulator is going to operate like a 1.5Watt heater, and if you don’t have enough heat sinking attached it will may overheat and go into thermal shutdown.
(Like the 5V regulator did on my original laser harp design)
So if the power dissipated is not that high, the cheapest solution would be to use the regulator.
Switching Convertors
A better, more efficient method is to use a “Switching” power supply. These take the input voltage (18V) and turn it on and off very quickly (thousands of times per second). The amount of time the voltage is on, compared to the amount of time it is off is called the “duty cycle”. So if I wanted to convert 18V to 12V I would need a duty cycle of 2/3. This is then fed through a network to smooth it back out to DC. I recently built some efficient DC converters for a robotics project. It was important to make them switching as they would not drain the battery as much as a regulated power supply.
AC to DC
If Dan wants to tap just the AC power then this has to be regulated and stepped down first. The old school way of doing this is to use a transformer with windings that get you close (but slightly above) the voltage you want. Eg – 110V to 16V would be a good step down. Then the 16V AC is fed into a full wave rectifier array of diodes that do full wave rectification, and then finally through 2-3 large capacitors to smooth the voltage down to something usable.
It’s worth pointing out that you can get switching power supply units that run off AC directly. The AC has to rectified and smoothed first, but then the full 110V is switched on and off to generate the voltage you require. The beauty of these units is that they can run on either 110V or 220V unmodified, the circuitry just monitors the output and adjusts the duty cycle of the switching to deal with whatever input voltage you pass in.
Probably the best thing for Dan to do is check out electronic surplus websites and pick up a 12V or 5V switching “wall wart” and then install this inside the case. They are small, efficient, and sometime go on sale for a dollar or two.
Steve Hobley maintains the blog “This week, I have been mostly working on…” all about his experiments and adventures in electronics, lasers, music, and fringe science.
You can contact Steve here: http://www.stephenhobley.com/blog
Basic Electronics Bridge Rectifier tutorial(Tishitu Electronics) Jaipur Rajasthan India
|
|
General Electric DS5201-A2S11 DS5201A2S11 Rectifier Bridge Stack Assembly $1,528.95 |
|
|
500W Wind Grid Tie Power Inverter wit bridge rectifier $995.00 |
|
|
Lot of 2 Geoenergy Rectifier PCA Bridge 191498 (4427) $399.99 |
|
|
Siemens 75Z331D1 1D Bridge Rectifier SS0476 USED $380.95 |
|
|
Syntron 75Z331-D1 75Z331D1 Bridge Rectifier USED $380.95 |
|
|
Reel of 3000 Central Semiconductor CBRHDSH1-100 TR13 Bridge Rectifier SMD $359.99 |
|
|
Siemens Y2180B1B1 Single Phase Bridge Rectifier USED $349.95 |
|
|
D2511 DGH Prog Input Bridge Rectifier Rare! $259.99 |
|
|
Gentron T485G Bridge Rectifier 5-20Hp USED $266.00 |
|
|
New 1000pcs 2W04 2A 400V Bridge Rectifiers $265.99 |
|
|
NEW RECTIFIER BRIDGE MODULE SKD100GAL123D SEMIKRON MODULES $244.99 |
|
|
500pcs Table Bridge Rectifier Diode BR610 6A 1000V UL HY $221.50 |
|
|
1000 pcs Bridge Diode Rectifier KBP206 KBP-206 2A 600V UL $172.50 |
|
|
Semikron Power Bridge Rectifiers IC SKD115/16 $198.00 |
|
|
500W wind power generator bridge rectifier DC 22V-60V $199.90 |
|
|
500W Wind Grid Tie Power Inverter wit bridge rectifier $199.90 |
|
|
1000 PCS MB6S SMD B6S Bridge Rectifier 0.5A 600V /Free Registered Mail $185.99 |
|
|
1000 PCS DB107S SMD DB107 1000V 1A BRIDGE RECTIFIER /Free Registered Mail $169.99 |
|
|
1000 PCS DB107 DIP-4 DB-107 1000V 1A BRIDGE RECTIFIER /Free Registered Mail $169.99 |
|
|
NEW RECTIFIER BRIDGE MODULE DDB6U145N16L EUPEC MODULES $159.99 |
|
|
NEW RECTIFIER BRIDGE MODULE DDB6U145N16L12H8 EUPEC MODULES $159.99 |
|
|
3000 PC’S P/N MB2S Diode Rectifier Bridge Single 200V 0.5A 4-Pin SOIC $149.99 |
|
|
200 Gbx packag Silicon Passivated Bridge Rectifier GBU1010 10A 1000V HY GBU1010C $132.50 |
|
|
1000 PCS DB104G DIP-4 DB104 Diodes Bridge Rectifier 400V /Free Registered Mail $159.99 |
|
|
LOT OF 5PCS NEW DF75AA160 SANREX BRIDGE RECTIFIER $110.00 |
|
|
200PCS KBPC1010 10A 1000V Bridge Rectifier NEW $155.00 |
|
|
Nos OEM GM Delco Alternator Rectifier Bridge 10472095 1991 99 Cadillac Chevrolet $145.00 |
|
|
40x Bridge Rectifier 3 Phase Diode 35A Amp 1000V SQL35A $150.00 |
|
|
40x Bridge Rectifier 3 Phase Diode 20A Amp 1000V SQL20A $150.00 |
|
|
40x Bridge Rectifier 3 Phase Diode 40A Amp 1000V SQL40A $150.00 |
|
|
40x Bridge Rectifier 3 Phase Diode 50A Amp 1000V SQL50A $150.00 |
|
|
100pcs KBPC2510 KBPC-2510 25A 1000V Bridge Rectifier $149.99 |
|
|
100pcs KBPC2510 KBPC-2510 25A 1000V Bridge Rectifier $149.99 |
|
|
100pcs KBPC2510 KBPC-2510 25A 1000V Bridge Rectifier $149.99 |
|
|
30X SQL5010 / SQL50A Bridge Rectifier 3 Phase Diode 50A 1000V $148.00 |
|
|
Henry 24050 diode block x2 rectifier bridge full wave high voltage $139.95 |
|
|
10 pcs x 36MT160 35 Amp 1600 Volt 3 Phase Bridge Rectifier $138.00 |
|
|
200 Kbx Package Silicon Passivated Bridge Rectifier Diode KBU810 8A 1000V UL HY $102.00 |
|
|
New 500pcs 2W04 2A 400V Bridge Rectifiers $135.99 |
|
|
Nos OEM GM Delco Alternator Rectifier Bridge D3992 10470609 $125.00 |
|
|
LOT OF 5PCS NEW DF30AA140 SANREX BRIDGE RECTIFIER $85.00 |
|
|
100pcs GBU808 GBU-808 8A 800V Bridge Rectifier $129.99 |
|
|
100pcs KBU1010 KBU-1010 10A 1000V Bridge Rectifier $129.99 |
|
|
100pcs GBU808 GBU-808 8A 800V Bridge Rectifier $129.99 |
|
|
100pcs KBU1010 KBU-1010 10A 1000V Bridge Rectifier $129.99 |
|
|
100pcs KBU1010 KBU-1010 10A 1000V Bridge Rectifier $129.99 |
|
|
100pcs GBU808 GBU-808 8A 800V Bridge Rectifier $129.99 |
|
|
150 PCS KBP310 3 Amp Bridge Rectifier 50 to 1000 Volts /FREE Registered Mail $129.99 |
|
|
NEW STANCOR RECTIFIER TRANSFORMER 1500 FULL WAVE CT 750 BRIDGE 375 HALFWAVE TP-4 $119.00 |
|
|
LOT OF 5PCS NEW DF30AA160 SANREX BRIDGE RECTIFIER $80.00 |
|
|
NEW LOT 5 PCS SANREX DF30AA160 BRIDGE RECTIFIER $80.00 |
|
|
NEW RECTIFIER BRIDGE MODULE DDB6U104N16RR EUPEC MODULES $119.99 |
|
|
10 X SEMIKRON SKD 30/04 A1 BRIDGE MODULE RECTIFIER SKD3004A1 $99.00 |
|
|
NEW RECTIFIER BRIDGE MODULE CVM30AA80 SANREX MODULES $115.99 |
|
|
Fuji Electric 6RI30B-060 6RI30B060 Bridge Rectifier Module NEW-NO BOX $115.00 |
|
|
NEW 1 PCS SKBT40/12 SKBT4012 SKBT40-12 SEMIKRON BRIDGE RECTIFIER $80.00 |
|
|
50,BRIDGE RECTIFIER -Model: GBPC5010 / 50A 1000V NEW ay $112.00 |
|
|
Sanrex DF200AA160 3 Phase Bridge Rectifier Diode $100.00 |
|
|
NEW RECTIFIER BRIDGE MODULE DDB6U205N16L EUPEC MODULES $104.99 |
|
|
MCC MICRO BRIDGE RECTIFIER 6A 800V CASE LOT 200 PIECES NEW 2011 $99.95 |
|
|
35 Amp 600 Piv Bridge Rectifier 35 AMP BRIDGE. 600 P.I.V. 1 1/8″ square…. |
|
|
50 Amp 1000V Bridge Rectifiers (Pack of 6) $23.99 50A 1000V Single Phase Bridge Rectifier. Universal 4-way terminals for snap-on, wrap-around, solder or board mounting. Pack of 6…. |
|
|
4A, 400V Full-Wave Bridge Rectifiers KBU401 # NTE532981704 (pack of 10) $19.50 4A, 400V Full-Wave Bridge Rectifiers KBU401… |
|
|
NINCO Lap Counter Bridge N-Scorer $89.99 Simple to operate, you can use the N-Scorer with NINCO, Scalextric, SCX, Artin, and other 1/32 systems if you put a couple of blocks under both sides. It works perfectly with Carrera track as well. Note: Due to the angle of the light beam from the N’Scorer, there can be problems counting laps for lower profile cars (such as F1 cars) on the narrow track of SCX, Scalextric and Artin. Other features:… |
|
|
Mini Art Plastics German Village House $25.37 This is the 1/35 scale German Village House from MiniArt. FEATURES: Unassembled plastic model kit Parts attached to a part tree 1/35 scale Intricate details 1/35 scale Dragon Fallen Comrade (Aachen 1944) ’39-’45 Series INCLUDES: This kit contains 126 unpainted parts for the German Village House and 67 unpainted parts for the Dragon figures Instruction sheet REQUIRES: Painting and assembly with … |
|
|
NINCO American Speedway Slot Car Set; 1/32 scale $171.99 This is the Ninco 1/32 American Speedway Figure 8 slot car track with Two Corvette GT3 Slot Cars. This track set includes two NINCO 1 Series Corvette GT3 Z06 race cars; the “Monza” and “Phoenix”, both with NINCOs powerful NC-11 inline motors! These cars race each other on a figure-8 circuit that measures 33″ x 101″, providing limitless entertainment. The American Speedway set includes 19 feet of t… |
|
|
NTE 5326 600V 25A Bridge Rectifier $7.00 NTE 5326 600V 25A Bridge Rectifier… |
|
|
NightFire Fixed DC Voltage Regulator Power Supply Kit (+12v) $7.99 This is the +12v Power Supply Kit. It is a fixed, Positive 12 Volt Power Supply designed for the 7800 series of Voltage Regulators. It includes a 1amp Bridge Rectifier with 2 large Aluminum Electrolytic Capacitors for initial filtering. There is also a .1uF cap for some noise filtering and a 1K bleeder resistor across the filter capacitors. The output has a small filter cap and a Red LED with a 47… |