Simple Adjustable Voltage Source
A simple but less efficient method of controlling a DC voltage is to use a voltage divider and transistor emitter follower configuration.
LM317T Voltage Regulator with Pass Transistor
The LM317T output current can be increased by using an additional power transistor to share a portion of the total current. The amount of current sharing is established with a resistor placed in series with the 317 input and a resistor placed in series with the emitter of the pass transistor.
LM317T Variable Voltage Regulator
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.
Flyback Transformer Driver
This is an efficient flyback driver for modern cylindrical rectified television flybacks. Many sites doesn't provide circuits driving these transformers, they simply say that they are bad.
2500W Phase Control
This circuit controls resistive and inductive loads up to 2,500W. Its main functional device is an integrated phase control circuit - Siemens TLE3103.
High And Low Voltage Cut Off With Time Delay
The power line fluctuations and cut-offs cause damages to electrical appliances connected to the line. It is more serious in the case of domestic appliances like fridge and air conditioners. If a fridge is operated on low voltage, excessive current flows through the motor, which heats up, and get damaged.
Solid State Power Controller
The ckt is built around two 555 timer ICs. U1 and U2. U1 is wired as a variable duty cycle oscillator with a constant time period of around 0.1 second. Duty cycle can be varied from 0 to 100 per cent by R4 potentiometer.
Dual Voltage Power Supply
The following circuit Diagram of (DUAL VOLTAGE POWER SUPPLY ) can be used for Misc.. application. It requires a few components to built. The most important components of this circuit are REGULATORS.
NiCd - NiMH Charger
The charger is build around a LM317 adjustable regulator.
Pulse Charger for reviving Lead Acid batteries
If you own a motorcycle, a motor home, a caravan, a lawn mover, a day cruiser or maybe a vintage car you must at some point had to write off a lead acid battery. When a battery is improperly charged or allowed to self-discharge as occurs during non-use, sulphate crystals build up on the battery's plates.
TTL Power Supply with Crowbar protection
Power supplies that are intended to be used with TTL logic circuitry must guard against over-voltage, which can destroy TTL chips very rapidly. The duration of over-voltage that can destroy TTL chips is much too brief to trigger any conventional fuse, so that only other semiconductor circuits can play any useful part in protecting a circuit against the type of failure of a stabilizer that leads to excessive voltage.
500W low cost 12V to 220V inverter
Using this circuit you can convert the 12V dc in to the 220V Ac.
Solar charger for lead-acid batteries
This circuit is intended for charging lead-acid batteries with a solar panel. The customary diode that prevents the battery from discharging through the solar panel has been replaced by a FET-comparator combination. The charger will stop charging once a pre-set voltage (temperature compensated) has been reached, and recommence charging when the voltage has dropped off sufficiently.
0-50V 2A Bench power supply
Variable voltage power supply for laboratories. With two ICs can take different output voltage and amperage.
Voltage Inverter II
This simple and inexpensive circuit can produce a dual voltage from a single supply input.
This simple circuit is a good solution to the powering a dual supply op amp from a single battery problem. The circuit simply takes a positive voltage and inverts it. It uses only one 555 timer and a few other passive components, so it doesn't add much in the way of size and cost to a project.
LASER Power Supply
If you have ever worked with lasers, you know how fun and interesting it can be, you also know how expensive it can be. The high voltage power supplies for the laser tubes are often more expensive then the tubes themselves.
Have you ever wanted to run a TV, stereo or other appliance while on the road or camping? Well, this inverter should solve that problem.
Fixed Voltage Power Supply
The fixed voltage power supply is useful in applications where an adjustable output is not required. This supply is simple, but very flexable as the voltage it outputs is dependant only on the regulator and transformer you choose. The maximum output current is 1.5A.
Variable DC Power Supply
A Variable DC Power Supply is one of the most useful tools on the electronics hobbyist's workbench.
LM317 VARIABLE POWER SUPPLY
A truly timeless circuit. 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.
Regulated 12 Volt Supply
This circuit above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0.7 Volts are dropped across the transistors b-e junction, leaving a higher current 12.3 Volt output supply. This circuit can supply loads of up to 500 mA. This circuit is also known as an amplified zener circuit.
Nicad Battery Charger
This simple charger uses a single transistor as a constant current source.
Dual Regulated Power Supply
In this circuit, the 7815 regulatates the positive supply, and the 7915 regulates the negative supply.
Basic 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.
Ni -Cd Batteries Charger
The NiCd charger takes approximately 12-15 hours of charge at 50mA (For AA-batteries).
Fuse Monitor - Alarm
This device monitors a fuses in your circuits. LED turns on when fuse is blown.
Rectification using a Gyrator Circuit
Current rectifier for large loads without large capacitors. It uses transistor 2N3055 as an active component.
Variable Power Supply
Using the versatile L200 voltage regulator, this power supply has independent voltage and current limits. Voltage output from about 3 to 15 volts.
Fast Electronic Fuse
This circuit is based on simple Ohms law. It uses voltage drop on a resistor to determine current strength and turns device off if it's to high. Circuit is designed to operate on 230V. threshold current is adjustable.
Soft Start PSU
Two soft start power supply.
12 Volt 30 Amp PSU
12 Volt 30 Amp power supply unit circuit diagram
13 Volt 20 Amp PSU
This is a Regulated DC power supply with short circuit protection and with current limiter. It delivers safely around 20Amps at 13.8V
High Current Power Supply
High current power supply circuit diagram with 2n3055. Voltage is stabilised.
Dual Polarity Power Supply
This dual polarity power supply is easy to build, requires few parts, and is adjustable from 0-15 volts.
Portable CD Player Adapter For Car
Portable CD Player Adapter For Car. Changes 12V voltage from your car, to 9 or less volts for cd player or some other device.
6V to 12V Converter
This inverter circuit can provide up to 800mA of 12V power from a 6V supply
Transformerless Power Supply
This supply uses no heavy step down transformer and has an extremely low parts count.