AC-DC & DC-DC Circuits
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This power supply circuit is highly stabilized that its output voltage will drop only 0.005% even though the load changes from 0 to 100%. Another excellent capability is that the output voltage will change only by 0.01% if the input voltage fluctuates. The....
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This 6V to 12V converter circuit is made with an IC from SGS with several additional components. The IC is a TDA2003 but it can be replaced with a TDA2002. The cost of building the 6volts to 12 volts converter should be low enough to justify constructing it....
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This 3 volts Car Adapter circuit is based on a standard LT1074CT switching regulator IC. The schematic shows the LT1074CT used as a positive step-down or ‘buck’ converter. The ‘switcher’ is used to convert a +12-volt car battery voltage down to +3 volts for....
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This simple variable power supply circuit has a low production cost and delivers an output voltage between 1,5 V and 15 V with a 500 mA maximum current. Its stabilization is better than 2% if the current consumption do not exceed 350 mA. The variation of the....
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4 simple 12Vdc power supply circuits with output voltages around 12V. First power supply circuit is built with BD139, one zener diode and a few passive components. Each of the schematic is very simple to construct and will function without problems if you....
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This regulator is suitable for devices that need up to 1mA. For higher output current, the resistors would have to be scaled down in reverse proportion to the peak current expected. With the resistor values shown, the regulator draws a current of only....
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This unit delivers 0 to 20 volts at up to 4 amps in 0.1 volt increments. The entire device runs on a PIC16F870 (about $3 in small quantities). This is basically a switching power supply with the voltage regulation done in software. The PIC used here has....
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his circuit is just an implementation of the 7805 integrated voltage regulator. What this little component does is to lower a voltage and stabilize it by reducing noise and ripple, in order for circuits to have the constant voltage needed to work correctly...
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I didn't realize till the other day that I have never shown a circuit for a standard power supply. Shown below is a supply that will use any of the LM78XX series of voltage regulators. The transformer in the circuit will vary depending on which regulator you....
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I use this power supply for applications that doesn't use too mucho power. It can provide power to circuit that uses less than 100mA without any problem. The disadvantage of this circuit is the danger of an electrical shock, so it cannot be used if the....
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The high voltage section of the CRT is unchanged from the original vacuum tube oscilloscope used as the basis of this design. The CRT requires shielding from the main power transformer. Cold roll steel around the CRT does not provide enough shielding from....
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The power supply, with electronic stabilisation - mainly those of laboratories - it should they are protected from ??over current?? that emanates from short-circuits, erroneous association or damage of repaired appliance. The circuit offers effective....
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This circuit of power supply, are very simple in the manufacture, the finding of his materials , is very easy and cost, small. The output voltage is stabilised and is regulated in the region from 0V until + 15V dc, with biggest provided current 1 A. The....
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Here they exist two regulator circuits, that use the IC L200, as regulator of voltage and current, the company SGS-Thomson, which give these circuits. In circuit Fig.1, we can regulate the output voltage, with the RV1, while in the Fig.2, we can regulate....
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Many times we needed a variety of voltages, from a battery 12V. With the circuit, we can take voltages smaller or bigger, positive or negative, from a battery 12V. The idea is based in oscillator roughly 7KHZ, round the R1, C28, that lead the remainder gates....
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This power supply is able to deliver adjustable center-tapped DC from 0 to about 30 volts, as well as AC directly from the Variac and from the main transformer before the rectifier. What's primitive by today's standard is that it is not voltage regulated;....
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Up to 10 A continuous output current, or operation with 50 % ESD and 18 A peak current are possible without a fan if sufficient natural air flow is present and the ambient temperature does not exceed 30 °C. A small CPU fan (40 x 40 mm) should be used for....
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This circuit is a dual voltage regulated power supply, +12, -12, 0 volt. It uses the 7812 and 7912 regulators. You need a 18VCT, 1A transformer at input...
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TR1 provides a constant current to a bank of three zener diodes, thus maintaining a constant voltage independant of supply voltage variations. The resistor Rx is used to sense the PSU output current and to switches off the current to the zener diodes should....
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This project has two options. It can be a mains operated project, using a 2155 or 2156 transformer or it can be connected to a plug pack.
We recommend it be connected to a 16v AC 1 amp plug pack as these are double insulated and provide complete safety for....
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This project uses the 1.2v rechargeable battery and solar panel from a Solar Garden Light. These lights can be bought for less than $5.00 in most $2.00 shops or similar shops that sell general household items.
We are also using the housing for this project....
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It will accept AC from 6v to 18v or DC from 9v to 18v and any current up to 1 amp.
The diode bridge on the input converts AC to DC and it doesn't matter which way around the leads are connected as the diodes compensate for either direction.
If a DC plug....
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Full short-circuit and overcurrent protection is given by this circuit suitable for workbench applications in technical schools and laboratories where there is a need to work directly with the mains. Additional features are a clearly visible red lamp....
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Most of the power supply failure indicator circuits need a separate power supply for themselves. But the alarm circuit presented here needs no additional supply source. It employs an electrolytic capacitor to store adequate charge, to feed power to the alarm....
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Opamps are very useful. But one of their major drawbacks is the requirement of a dual supply. This seriously limits their applications in fields where a dual supply is not affordable or not practicable.
This circuit solves the problem to a certain extent.....
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The circuit is a MOSFET based linear voltage regulator with a voltage drop of as low as 60 mV at 1 ampere. Drop of a fewer millivolts is possible with better MOSFETs having lower RDS(on) resistance. The circuit in Fig. 1 uses 15V-0-15V secondary from a....
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This over/under voltage cut-out will save your costly electrical and electronic appliances from the adverse effects of very high and very low mains voltages. The circuit features auto reset and utilises easily available components. It makes use of the....
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Voltage variations and power cuts adversely affect various equip- ment such as TVs, VCRs, music systems and refrigerators. This simple circuit will protect the costly equipment from high as well as low voltages and the voltage surges (when power resumes). It....
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This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket. Those transformers are easily....
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The following circuit is an example how to get power from RS-232 serial port. It gives regulated +5V power for logic circuits and also unregulated positive and negative power supplies for RS-232 transmitting circuit. The circuit gives only few milliampres....
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The circuit is shown in Figure 1, and as described above, uses a voltage doubler rectifier. Diodes D1 and D2 are 1N4004 or similar. From there, a pair of resistors provide additional smoothing to the secondary filter caps. R3 is used to balance the voltage....
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I made the power supply which makes about +30V with +5V power supply.
The direct current is changed into the alternating current by the oscillator which used the schmitt trigger inverter which has the hysteresis characteristic and the resonance circuit. The....