uninterrupted power supply circuit diagram

uninterrupted power supply circuit diagram Schematic

The circuit drawn pertains to a regular industrial UPS (Uninterruptible Energy Provide), which reveals how the batteries get control during an outage in electrical supply or variation beyond the typical limits of the voltage line, without disruption around the operation providing a constant regulated output (5 Volts by LM7805) and an unregulated supply (twelve Volts).

The input to the main winding of the transformer (TR1) is 240V. The secondary winding could be raised up to fifteen Volts in case the value is at the very least twelve Volts operating two amp. The fuse (FS1) acts as being a mini circuit breaker for protection against brief circuits, or a defective battery cell in truth. The presence of electrical energy will cause the LED 1 to light. The light of LED will set off on power outage as well as the UPS battery will get over

The circuit was designed to offer more versatile pattern wherein it may be customized by employing numerous regulators and batteries to create regulated and unregulated voltages. Making use of two 12 Volt batteries in sequence and a positive input 7815 regulator, can control a 15V supply.

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NiMH Battery Charger Circuit

NiMH Battery Charger Circuit

Nickel Metal Hydride battery that demands present regulated charging. The charger offers 140 mA current for quick charging of the battery.Power provide part consists of a 0-18 volt AC one Ampere step-down transformer, a full wave bridge rectifier comprising D1 through D4 along with the smoothing capacitor C1. Current regulation is accomplished from the action of R1,R2 as well as the Epitaxial Darlington PNP transistor Tip 127. Resistor R1 retains the charging current to 140 milli amperes. LED and resistor R2 plays an significant role to manage the base current of T1 and therefore its output. Around 2.6 volts drop develops across the LED which seems in the base of T1. Emitter - base junction of T1 drops about 1.two volts. So two.6 - 1.2 volts offers 1.40 volts. Therefore the current passing by means of R1 are going to be 1.40 V / ten = 0.14 Amps or 140 Milli Amps. The LED act because the charging status indicator. LED lights only when the battery is connected to the output of circuit and the input voltage is regular.

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UA78G/UA79G Variable Power Supply Circuit Diagram

UA78G/UA79G Variable Power Supply Circuit Schematic

A abiding capricious ability accumulation with an adjustable achievement voltage from 5 volts to 30 volts can be calmly complete with the regulator ICs UA78G or UA79G. These ICs alter from the accepted three-terminal regulator back their achievement voltages are adjustable by a voltage akin at their ascendancy inputs. The best accepted delivered by these ICs is 1 ampere.

The able voltage charge be at atomic 5 volts college than the adapted achievement akin to advance stability. The ascribe voltage about charge not beat 40 volts. The best amusement of the IC is 15 watts.

The capricious ability accumulation ambit presented actuality is advised to accord best voltage akin of 28 volts. If P1 is replaced with 25K potentiometer, the regulator can bear up to a best of 30 volts. Capacitors C1 and C2 balance the IC and they charge be affiliated as abutting as accessible to the IC terminals.

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LT1300 Solar Powered Power Supply

LT1300 Solar Powered Power Supply Circuit

This architecture was generated as allotment of a alien acclimate base project. One of the requirements of the architecture is that it accept a solar-powered accumulation with rechargeable batteries. This architecture is based on a photovoltaic arrangement accessible from Radio Shack alleged a BatterySAVER (part cardinal 980-1045). It was advised to allegation your car array during the day. They allegedly aren't actual accepted because you can aces them up for $15. The affidavit claims an achievement of 1 watt but I begin that at apex in Atlanta, the ability was a little les than bisected a watt. Maybe at the equator during the autumnal equinox...

For my application, the boilerplate cesspool off the batteries would is abundant abate than the charging accepted (50mA). If your appliance has college boilerplate accepted requirements, again R1 will charge to be adapted accordingly:

R1=64mV/(50mA+Average Amount Current)

Don't try to cull too abundant accepted admitting because the solar console can alone accommodate 500mW and the batteries charge 40% of that. That leaves 300mW for your load.

The architecture is based on four anatomic blocks: 1) a 50mA accepted antecedent apprenticed by the solar cells, 2) three AAA NiCAD batteries with a 500mAHr capacity, 3) a 5V, 400mA switchmode regulator, and 4) a low dropout 3.3V 150mA beeline regulator. If you accept no charge for 3.3V again U3 and C4 can be eliminated. If you alone charge 3.3V again U3 and C4 can be alone and pin 2 of U2 can be affiliated to arena - this will catechumen U2 to a 3.3V switchmode regulator.

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7812 IC 12 Volt 30 Amp PSU Circuit

Using a distinct 7812 IC voltage regulator and assorted outboard canyon transistors, this ability accumulation can bear achievement amount currents of up to 30 amps.

Notes:

The ascribe agent is acceptable to be the best big-ticket allotment of the absolute project. As an alternative, a brace of 12 Volt car batteries could be used. The ascribe voltage to the regulator charge be at atomic several volts college than the achievement voltage (12V) so that the regulator can advance its output. If a agent is used, again the rectifier diodes charge be able of casual a actual aerial aiguille advanced current, about 100amps or more. The 7812 IC will alone canyon 1 amp or beneath of the achievement current, the butt actuality supplied by the outboard canyon transistors. As the ambit is advised to handle endless of up to 30 amps, again six TIP2955 are active in alongside to accommodated this demand. The amusement in anniversary ability transistor is one sixth of the absolute load, but able calefaction biconcave is still required. Best amount accepted will accomplish best dissipation, so a actual ample calefaction bore is required. In because a calefaction sink, it may be a acceptable abstraction to attending for either a fan or baptize cooled calefaction sink. In the accident that the ability transistors should fail, again the regulator would accept to accumulation abounding amount accepted and would abort with adverse results. A 1 amp agglutinate in the regulators achievement prevents a safeguard. The 400mohm amount is for analysis purposes alone and should not be included in the final circuit.

Calculations:

This circuit is a fine example of Kirchoff's current and voltage laws. To summarise, the sum of the currents entering a junction, must equal the current leaving the junction, and the voltages around a loop must equal zero. For example, in the diagram above, the input voltage is 24 volts. 4 volts is dropped across R7 and 20 volts across the regulator input, 24 -4 -20 =0. At the output :- the total load current is 30 amps, the regulator supplies 0.866 A and the 6 transistors 4.855 Amp each , 30 = 6 * 4.855 + 0.866. Each power transistor contributes around 4.86 A to the load. The base current is about 138 mA per transistor. A DC current gain of 35 at a collector current of 6 amp is required. This is well within the limits of the TIP2955. Resistors R1 to R6 are included for stability and prevent current swamping as the manufacturing tolerances of dc current gain will be different for each transistor. Resistor R7 is 100 ohms and develops 4 Volts with maximun load. Power dissipation is hence (4^2)/200 or about 160 mW. I recommend using a 0.5 Watt resistor for R7. The input current to the regulator is fed via the emitter resistor and base emitter junctions of the power transistors. Once again using Kirchoff's current laws, the 871 mA regulator input current is derived from the base chain and the 40.3 mA flowing through the 100 Ohm resistor. 871.18 = 40.3 + 830. 88. The current from the regulator itself cannot be greater than the input current. As can be seen the regulator only draws about 5 mA and should run cold.

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+50V 3A Stabilized & Regulated Power Supply

+50V 3A Stabilized & Regulated Power Supply Circuit

Many times we bare a stabilized, calm adapted ability accumulation and aerial almost achievement voltage. These blueprint him it awning our circuit. It 's a ambit that can accord in his avenue + 40V until + 60V 3A, with accompanying stabilization. The abstracts that use is actual simple and will not abide difficulties in the manufacture, is abundant you are accurate assertive points. 1 ] For achievement voltages abate of + 50V until + 40V, the Q1 is hot enough, so that it needs one big heatsink. 2]For achievement voltages bigger of + 50V up to + 70V, the stabilization is not satisfactory. Conclusion: ideal achievement voltage is + 45V until + 60V. In the ambit pontesometer RV1, is acclimated in adjustment to we change the achievement voltage amid + 40V until + 70V, we can about and conceivably it should, him we alter with two affiliated resistors, back finishe the regulation, in the adorable price. The acumen is, that with time is presented change of achievement voltage, up to 3V, with affiliated pontesometer. ATTENTION!!! The absolute avenue accord in point [ A ] and the avenue of 0V in point [ B ], which should not be affiliated in the ground.

+50V 3A Stabilized & Regulated Power Supply Part list

* R1=10Kohm
* R2=1 ohm 5W
* R3=3.9 ohms 1W
* R4=6.8Kohm 1W
* R5=390 ohms 1W
* R6=100Kohm 0.5W
* R7=1.2Kohm 1W
* R8=1.8Kohm 0.5W
* R9=3.3Kohm 0.5W
* RV1=470 ohms pot.
* C1-2-4=4700uF 100V
* C3-5=100nF 250V MKT
* Q1=2N3055 on heatsink
* Q2=BD162 or BD243 or BD543
* Q3=BC303 or BC461
* D1....4=Bridge 15A
* D5=LED RED 5mm
* D6-7=10V 1W Zener
* D8-9-10=1N4007
* T1=230Vac / 55V 3A

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LM317 and LM337 regulator IC For Dual Variable Power supply

D is 1N4001 diode or any of the same maximum current capacity. Fuse must be 0.5A, 250V or much lower amperage rating. Transformer is 220VAC to 26V -0 -26V, 2A or 120V to 26V -0 – 26V rating of 60VA or higher, bridge diode must be rated 3A or higher for good circuit operation. The resistors used are rated 1/2W.The input capacitor must be 4700uF or larger for better regulation and stability. The output capacitor Cout is 10uF.

This power supply uses LM317 for the positive regulation that can supply an output of 0V to 28V dc at a maximum current of 1.5A (with heatsink or cooling fan). The output voltage of the positive regulator is given by the formula:
Vout = 1.25(1 + 5K/240) + (100uA) (5K) - 1.4V
Where,
240 is the resistance from adjust and output terminal of LM317
5K is the resistance of the potentiometer connected to adjust terminal
-1.4V is the forward voltage of the two diode connection

Similar to LM317 operation, LM337 control the negative regulation of output voltage to ensure its output to 0V to -28V of a maximum current of -1.5A (of course wit heatsink). The variable negative output is given by the formula:
Vout = -1.25(1 + 5K/240) – (100uA) (5K) + 1.4V
Where,
240 is the resistance from adjust and output terminal of LM337
5K is the resistance of the potentiometer connected to adjust terminal
1.4V is the forward voltage of the two diode connection



Note: This power supply project is powered through 220V main and can cause electrocution

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5 volt CMOS to 12 volt/ 25 Watt Loads Interfacing Circuit

The circuit below is designed to be used with the bi-directional lamp sequencer shown above on this same page. Two additional transistors are used to increase the current from the 74HCT138 decoder to control 12 volt 25 watt lamps. A 6.8 volt/1 watt zener diode is used in series with the ground connection of all the CMOS ICs (74HC14, CD4516 and 74HC138s) so that the total voltage across the CMOS devices will be about 5.2 volts and the outputs will move from +12 to about +7 when selected. The 2N2905/PNP transistor stage is connected as an emitter follower which provides a high impedance to the decoder output and supplies about 80 mA of current to the base of the 2N3055 NPN power transistor which then supplies 2 or more amps to the 12 volt lamp. The voltage across the PNP transistor will be about 7 volts when it is turned on and the heat dissapation will be about 0.6 watts. That should't require a heat sink if several lamps are sequencing but it may get quite warm if the circuit is idle on a single output. The 2N3055 power transistor operates as a switch and drops very little voltage (less than 0.5) when conducting, and will not require a heat sink. Other transistors may be substituted such as the TIP29 or TIP31 for the 2N3055 and most any medium power (500mA) PNP for the 2N2905.

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1KW Space Heater Thermostat (SCR controlled)

Below is a thermostat circuit I recently built to control a 1300 watt space heater. The heater element (not shown) is connected in series with two back to back 16 amp SCRs (not shown) which are controlled with a small pulse transformer. The pulse transformer has 3 identical windings, two of which are used to supply trigger pulses to the SCRs, and the third winding is connected to a PNP transistor pair that alternately supply pulses to the transformer at the beginning of each AC half cycle. The trigger pulses are applied to both SCRs near the beginning of each AC half cycle but only one conducts depending on the AC polarity.

DC power for the circuit is shown in the lower left section of the drawing and uses a 1.25uF, 400 volt non-polarized capacitor to obtain about 50mA of current from the AC line. The current is rectified by 2 diodes and used to charge a couple larger low voltage capacitors (3300uF) which provide about 6 volts DC for the circuit. The DC voltage is regulated by the 6.2 volt zener and the 150 ohm resistor in series with the line limits the surge current when power is first applied.

The lower comparator (output at pin 13) serves as a zero crossing detector and produces a 60 Hz square wave in phase with the AC line. The phase is shifted slightly by the 0.33 uF, 220K and 1K network so that the SCR trigger pulse arrives when the line voltage is a few volts above or below zero. The SCRs will not trigger at exactly zero since there will be no voltage to maintain conduction.

The upper two comparators operate in same manner as described in the "Electronic thermostat and relay" circuit. A low level at pin 2 is produced when the temperature is above the desired level and inhibits the square wave at pin 13 and prevents triggering of the SCRs. When the temperature drops below the desired level, pin 2 will move to an open circuit condition allowing the square wave at pin 13 to trigger the SCRs.

The comparator near the center of the drawing (pins 8,9,14) is used to allow the heater to be manually run for a few minutes and automatically shut off. A momentary toggle switch (shown connected to a 51 ohm resistor) is used to discharge the 1000uF capacitor so that pin 2 of the upper comparator moves to a open circuit state allowing the 60 Hz square wave to trigger the SCRs and power the heater. When the capacitor reaches about 4 volts the circuit returns to normal operation where the thermistor controls the operation. The momentary switch can also be toggled so that the capacitor charges above 4 volts and shuts off the heater if the temperature is above the setting of the pot.

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Low Voltage High Current Time Delay Circuit

In this circuit a LM339 quad voltage comparator is used to generate a time delay and control a high current output at low voltage. Approximatey 5 amps of current can be obtained using a couple fresh alkaline D batteries. Three of the comparators are wired in parallel to drive a medium power PNP transistor (2N2905 or similar) which in turn drives a high current NPN transistor (TIP35 or similar). The 4th comparator is used to generate a time delay after the normally closed switch is opened. Two resistors (36K and 62K) are used as a voltage divider which applies about two-thirds of the battery voltage to the (+) comparator input, or about 2 volts. The delay time after the switch is opened will be around one time constant using a 50uF capacitor and 100K variable resistor, or about (50u * 100K) = 5 seconds. The time can be reduced by adjusting the resistor to a lower value or using a smaller capacitor. Longer times can be obtained with a larger resistor or capacitor. To operate the circuit on higher voltages, the 10 ohm resistor should be increased proportionally, (4.5 volts = 15 ohms).

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Variable Voltage Regulator With LM317T

The LM317T is a adjustable 3 terminal positive voltage regulator capable of supplying in excess of 1.5 amps over an output range of 1.25 to 37 volts. The device also has built in current limiting and thermal shutdown which makes it essentially blow-out proof.

Output voltage is set by two resistors R1 and R2 connected as shown below. The voltage across R1 is a constant 1.25 volts and the adjustment terminal current is less than 100uA. The output voltage can be closely approximated from Vout=1.25 * (1+(R2/R1)) which ignores the adjustment terminal current ``but will be close if the current through R1 and R2 is many times greater. A minimum load of about 10mA is required, so the value for R1 can be selected to drop 1.25 volts at 10mA or 120 ohms. Something less than 120 ohms can be used to insure the minimum current is greater than 10mA. The example below shows a LM317 used as 13.6 volt regulator. The 988 ohm resistor for R2 can be obtained with a standard 910 and 75 ohm in series.

When power is shut off to the regulator the output voltage should fall faster than the input. In case it doesn't, a diode can be connected across the input/output terminals to protect the regulator from possible reverse voltages. A 1uF tantalum or 25uF electrolytic capacitor across the output improves transient response and a small 0.1uF tantalum capacitor is recommended across the input if the regulator is located an appreciable distance from the power supply filter. The power transformer should be large enough so that the regulator input voltage remains 3 volts above the output at full load, or 16.6 volts for a 13.6 volt output.

LM317 Data Sheet

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High Current Regulated Power Supply

High Current Regulated Supply

The high current regulator below uses an additional winding or a separate transformer to supply power for the LM317 regulator so that the pass transistors can operate closer to saturation and improve efficiency. For good efficiency the voltage at the collectors of the two parallel 2N3055 pass transistors should be close to the output voltage. The LM317 requires a couple extra volts on the input side, plus the emitter/base drop of the 3055s, plus whatever is lost across the (0.1 ohm) equalizing resistors (1volt at 10 amps), so a separate transformer and rectifier/filter circuit is used that is a few volts higher than the output voltage. The LM317 will provide over 1 amp of current to drive the bases of the pass transistors and assumming a gain of 10 the combination should deliver 15 amps or more. The LM317 always operates with a voltage difference of 1.2 between the output terminal and adjustment terminal and requires a minimum load of 10mA, so a 75 ohm resistor was chosen which will draw (1.2/75 = 16mA). This same current flows through the emitter resistor of the 2N3904 which produces about a 1 volt drop across the 62 ohm resistor and 1.7 volts at the base. The output voltage is set with the voltage divider (1K/560) so that 1.7 volts is applied to the 3904 base when the output is 5 volts. For 13 volt operation, the 1K resistor could be adjusted to around 3.6K. The regulator has no output short circuit protection so the output probably should be fused.

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Variable DC Power Supply With LM317

This DC power supply circuit is adjustable using IC Voltage Regulator LM317. LM317 is a versatile and highly efficient 1.2-37V voltage regulator that can provide up to 1.5A of current with a large heat sink. It's ideal for just about any application. This was my first workbench power supply and I still use it.

Since LM317 is protected against short-circuit, no fuse is necessary. Thanks to automatic thermal shutdown, it will turn off if heating excessively. All in all, a very powerful (and affordable!) package, indeed.

Although voltage regulator LM317 is capable of delivering up to 37V, the DC power supply output circuit here is limited to 25V for the sake of safety and simplicity. Any higher output voltage would require additional components and a larger heat sink.

Make sure that the input voltage is at least a couple of Volts higher than the desired output. It's ok to use a trimpot if you're building a fixed-voltage supply.

Problems:
Follow all the safety precautions when working with mains voltage. Insulate all connections on the transformer.

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