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Power Supply Circuits
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AC-DC & DC-DC Circuits
When working with electronics, you always need one basic thing; power. This power supply is great for powering all kinds of electronic projects. It produces a well filtered, variable 1.2-30 volts at 5 amps. It is easy to build and the parts are easy to find.
High Current Power Supply
Since my page was first posted, I have received a number of emails asking about a high current power supply. I looked around, but couldn`t find one that was suitable. So, I designed this. It is a linear supply, which might have a few of you rolling your eyes, but it takes very few parts, is simple to build and can supply huge currents.
power supply (300V, 50mA + 6.3V, 3A max)
This regulated power supply was built as a simplified outboard version of a PSU in my first phono stage. Replacing hexfreds with tube rectifier eliminates the need for power-on sequencing. Chassis (salvaged from a hospital laser PSU) size is 180W*240D*100H mm with a 125W double-C core power transformer and a 10H/100mA choke inside.
Pedalboard Power Supply
Each of these ways have their own advantages and disadvantages. The multiple transformer way is easy to start small and work up to only as many power supplies as you need. It does, however, get more expensive as the number of supply outputs goes up. Suitable transformers are a bargain at Mouser, as #41PG006 is a 12V/0.06A transformer for under...
12 Volt 30 Amp PSU
Using a single 7812 IC voltage regulator and multiple outboard pass transistors, this power supply can deliver output load currents of up to 30 amps. The input transformer is likely to be the most expensive part of the entire project. As an alternative, a couple of 12 Volt car batteries could be used. The input voltage to the regulator must be...
1.3 Volt Power Source
This is a replacement power source for 1.3V mercury cells or other small batteries. It has many uses and I use this circuit in my computer to power a front panel multi adapter which has a digital thermometer. This circuit takes it power from a PC. The power connectors have colour coded wiring, red and black are a 12V supply, black and yellow are...
9 Volt 2 Amp PSU with 78S09
The circuit will work without the extra components, but for reverse polarity protection a 1N5400 diode is provided at the input, extra smoothing being provided by C1. The output stage includes C2 for extra filtering, if powering a logic circuit than a 100nF capacitor is also desirable to remove any high frequency switching noise.
Increasing Regulator Current
Although the 78xx series of voltage regulators are available with different current outputs, you can boost the available current output with this circuit. A power transistor is used to supply extra current to the load the regulator, maintaining a constant voltage. Currents up to 650mA will flow through the regulator, above this value and the...
Overvoltage Protection for the LM317
This is an add-on Over Voltage Circuit for the LM317 Regulator Circuit submitted by Matthew Hewson. It is a voltage regulator that allows a 6v portable supply to be derived from the 12v car battery. You can add a 6.2V zener diode and a LED to warn you when the input supply is overvoltage. If you could find a relay that would operate from 6.2v...
This circuit will generate a smaller DC output voltage from a larger DC input voltage.It is quick and simple to make and by changing the value of the zener diode, the circuit can be universally adapted to provide other output voltages.The circuit and all diagrams represent a DC convertor with 12V battery input and 9Volt DC output.
Dual Regulated Power Supply 15v
In this circuit, the 7815 regulatates the positive supply, and the 7915 regulates the negative supply. The transformer should have a primary rating of 240/220 volts for europe, or 120 volts for North America. The centre tapped secondary coil should be rated about 18 volts at 1 amp or higher, allowing for losses in the regulator.
Rectification using a Gyrator Circuit
To avoid excess ripple output on a power supply feeding a heavy load, usually a large value capacitor is chosen following the rectifier. In this circuit, C1 is only a 470uF capacitor. The gyrator principle uses the effect that the value of input capacitance at the base of a transitor is effectively multiplied by the current gain of the...
LM317 Regulator Circuit
The voltage regulator is an LM317T, and should accept up to about 14 volts without problems. It can handle up to 1 amp, but you WILL need a heatsink on the voltage regulator. I also added DC power jacks for input and output on my voltage regulator, a green power LED, and a red over-voltage LED. The over voltage LED uses a zener diode to switch...
Soft Start for PSU
Two soft start power supplies. The output voltage slowly increases to the desired output. The output voltage rises slowly and reaches 15 V in 5 seconds. In order to perform this soft-start function, the LM317 voltage regulator IC requires an external universal PNP transistor and the L200 uses its internal comparator (pin 2).
Supply Voltage Indicator
A novel supply voltage monitor which uses a LED to show the status of a power supply. This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the naked eye) yellow light. If the input voltage falls...
This circuit will supply up to about 20ma at 12 volts. It uses capacitive reactance instead of resistance; and it doesn`t generate very much heat.The circuit draws about 30ma AC. Always use a fuse and/or a fusible resistor to be on the safe side. The values given are only a guide. There should be more than enough power available for timers,...
4 Amps Universal PSU
A Universal Power supply based on the L200 regulator, which includes an outboard pass transistor to boost output currents up to 4 amps.
UPS Power Supply
This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply. This circuit can be adapted for other regulated and unregulated voltages by using different...
Variable Voltage Regulation
Controlling the output voltage from a regulator can be made variable in three ways:- 1. Using a fixed reference zener diode to increase the output by the value of the zener 2. A variable resistor for variable output, note that a voltage less than the nominal regulator is not possible 3. A chain of diode such as 1N4001, this increases the...
12 volt power supply (7812)
Please operate caution when building this power supply. It is run on standard 117 ac current - and under the right circumstances 117 ac can kill you. Use a plastic enclosure if possible to decrease chances of short-circuiting.
simple voltage doubler
this circuit rougly doubles the voltage of the input, however the current output is low. doubled output is at `V source.`
This circuit inverts the polarity of the input. output is limited to less that 200mA.
0.7 - 24V /2A Power Supply
A Variable DC Power Supply is one of the most useful tools on the electronics hobbyist`s workbench. This circuit is not an absolute novelty, but it is simple, reliable, "rugged" and short-proof, featuring variable voltage up to 24V and variable current limiting up to 2A. Well suited to supply the circuits shown in this website. You can adapt it...
Dynamo Current and Voltage Regulator
In the typical dynamo charging circuit, B+ and B- are the battery connections. D+ and D- go to the dynamo brushes, while DF is the field connection, with its other end returned to D+ inside the dynamo. Please note that not all dynamos return the field winding to the positive output! My regulator circuit, as shown here, works only with dynamos...
0-30 Volt Laboratory Power Supply
The linear power supply, shown in the schematic, provides 0-30 volts, at 1 amp, maximum, using a discrete transistor regulator with op-amp feedback to control the output voltage. The supply was constructed in 1975 and has a constant current mode that is used to recharge batteries.
0-15 Volt Tracking PS
The linear dual tracking power supply, shown in the schematic, provides 0-15 volts, at 1/4 amp, maximum, using a discrete transistor regulator with op-amp feedback to control the output voltage. The supply was constructed in 1975; the negative ouput voltage tracks the positive output voltage.
Voltage Inverter II
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.
6V to 12V Converter
This inverter circuit can provide up to 800mA of 12V power from a 6V supply. For example, you could run 12V car accessories in a 6V (British?) car. The circuit is simple, about 75% efficient and quite useful. By changing just a few components, you can also modify it for different voltages.
12 Vdc - 120 Vac Inverter
An Inverter is a device that converts 12 volts d.c to 120 volts a.c. , which is what we use in our homes. This project will handle about 300 watts, which is perfect for lights, small T.V.`s and radio equipment. This Inverter takes 12 volt d.c and steps it up to 120 volt a.c.
Regulator Combination Circuits
There are a number of ways to obtain the low voltages required to run small projects from the wall power outlet. The simplest way is to buy a factory-built molded supply which is designed to plug directly into the wall outlet. Some such supplies have an internal voltage regulator and need no additional parts, others provide an unregulated DC...
Adjustable Auto transformer
An isolation transformer and a variable auto transformer, very much like a Variac. Fuse 1 protects against gross overload. Lamp 1, across the Fuse 1, is a red incandescent pilot lamp and it lights up in the event of a blown fuse. Imagine how much time this would save when bringing up a stubborn power supply. Take note: Everything that can...
DC to DC Converter
The intended use of the 24 volts is to power an amplifier that will supply wave forms of up to a couple hundred Hz to bias a varactor or pair of varactors in an RF circuit. This meant that the current requirements would be low - probably a little over a milliamp. It also made me worry about recovery spikes from the rectifier, and harmonics from...
Free Energy Circuits
Battery Charger Circuits
Solar Cell Circuits
Current Limiting Circuits
Micro Power Circuits
High Voltage Circuits
Switching Power Supply Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
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