Showing posts with label voltage. Show all posts
Showing posts with label voltage. Show all posts
Saturday, November 8, 2014
Low Voltage Power Supply Without Transformer
The circuit diagram was designed to create a power supply without utilizing any transformer circuit. This circuit illustrates the advantages as well as the safety precautions to keep in mind.
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Power supplies are devices accustomed to provide electrical or other sort of energy to a load or cluster of load. A type of power supply that makes use of a transformer is the AC powered linear power supply. The voltage from the wall socket is converted by the transformer to produce a normally lower voltage. Switched-mode and AC/DC power supplies are the types that does not utilize the presence of transformers. These transformers are responsible for transmitting electrical supply from one circuit to another through its coils (windings).
Designing a transformerless power supply makes it more suitable for smaller installations, in any location, where the area may be limited. The circuit can manage the high current coming from the mains by supplying 12 Volts at 20mA. The reason behind using capacitive reactance rather than resistance is the fact the the type of current flowing into the circuit is alternating. It can also be used with fluctuating DC supply. The reactance adapts with the way the components react in the circuit in terms of frequencies. A fusible resistor can also be used to provide more safety.
As an output device, optical sensors are preferred by measuring the intensity change of light when the power is increased among other controllers like temperature controllers, light switches or timers. The capacitor C1 are connected across the mains supply to act as restrainer. These capacitors are usually tagged with safety standard measures, although they are usually more expensive type rather than ordinary capacitors. Placing two capacitors in parallel or increasing the value can give way to additional current.
The two zener diodes are responsible for supplying the low voltage because these types of diodes controls the output by setting their breakdown or desired voltage, as they flow to the rectifier. The rectifier is responsible for converting the AC to DC. Opposite conversion form DC to AC uses an inverter. If the circuit would require an output higher than 40mA, transformers would be more significant to use.
The comparison between transformerless and transformer-based power supplies is not easy to identify due to the technologies that each one offers in the market. But the primary difference between the two are the physical dimension, noise, efficiency and the intensity of harmonic distortion that they produce.
Source:www.zen22142.zen.co.uk
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Power supplies are devices accustomed to provide electrical or other sort of energy to a load or cluster of load. A type of power supply that makes use of a transformer is the AC powered linear power supply. The voltage from the wall socket is converted by the transformer to produce a normally lower voltage. Switched-mode and AC/DC power supplies are the types that does not utilize the presence of transformers. These transformers are responsible for transmitting electrical supply from one circuit to another through its coils (windings).
Designing a transformerless power supply makes it more suitable for smaller installations, in any location, where the area may be limited. The circuit can manage the high current coming from the mains by supplying 12 Volts at 20mA. The reason behind using capacitive reactance rather than resistance is the fact the the type of current flowing into the circuit is alternating. It can also be used with fluctuating DC supply. The reactance adapts with the way the components react in the circuit in terms of frequencies. A fusible resistor can also be used to provide more safety.
As an output device, optical sensors are preferred by measuring the intensity change of light when the power is increased among other controllers like temperature controllers, light switches or timers. The capacitor C1 are connected across the mains supply to act as restrainer. These capacitors are usually tagged with safety standard measures, although they are usually more expensive type rather than ordinary capacitors. Placing two capacitors in parallel or increasing the value can give way to additional current.
The two zener diodes are responsible for supplying the low voltage because these types of diodes controls the output by setting their breakdown or desired voltage, as they flow to the rectifier. The rectifier is responsible for converting the AC to DC. Opposite conversion form DC to AC uses an inverter. If the circuit would require an output higher than 40mA, transformers would be more significant to use.
The comparison between transformerless and transformer-based power supplies is not easy to identify due to the technologies that each one offers in the market. But the primary difference between the two are the physical dimension, noise, efficiency and the intensity of harmonic distortion that they produce.
Source:www.zen22142.zen.co.uk
Thursday, November 6, 2014
12KV High Voltage Generator
The hobby circuit below uses an unusual method to generate about 12,000 volts with about 5uA of current. Two SCRs form two pulse generator circuits. The two SCRs discharge a 0.047uF a 400v capacitor through a xenon lamp trigger coil at 120 times a second.
The high voltage pulses produced at the secondary of the trigger coil are rectified using two 6KV damper diodes. The voltage doubler circuit at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this circuit can’t produce a lot of current be very careful with it. A 12KV spark can jump about 0.75 of an inch so the electronic circuit needs to be carefully wired with lots of space between components.
Friday, October 17, 2014
Simple Solar Cell Voltage Regulator Circuit Diagram
This is a Simple Solar Cell Voltage Regulator Circuit Diagram. This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The circuit consists only of one 5V regulator, two transistors, two LEDs, five resistors, two capacitors, and one small battery. Although a 4-V battery is indicated, 4.5 V (3 alkalines in series) or 3.6 V (3 NiCd cells in series) will also work.
Solar Cell Voltage Regulator Circuit Diagram
The specifications of voltage regulator IC1 are mainly determined by the size and number of the solar cells and the current pull of the equipment connected to the output. Here the low-drop 4805 is suggested but other regulators may work equally well as long as you observe the output voltage of the solar cells. Transistors T1 and T2 are complementary types i.e. one each of the pnp and npn variety.
Although the ubiquitous BC557B (pnp) and BC547B (npn) are indicated, any small-signal equivalents out of the junk box will probably do. The values of voltage dividers R1/R6 and R3/R4 may need to be adjusted according to the type of transistor and its gain, or according to the desired voltage thresholds. Using the resistor values shown in the schematic, LED D2 turns on fully when the voltage is just above 5 volts.
LED D1 turns on when the voltage drops below 4.2 volts or so. Between those two thresholds, there is a sort of no man’s land where both LEDs are on dimly. A buzzer or other warning device could be connected across the terminals of LED D1 to give a more substantial warning if the voltage drops below operating limits. The current consumption of the circuit is about 20 mA at 5 V, and it decreases with the voltage supplied by the solar cells.
Monday, September 8, 2014
Simple Voltage monitor Wiring diagram Schematic
This is the simple Voltage monitor Circuit Diagram. This schema gives an early warning of the discharge of batteries. Zener diode Dl is chosen for the voltage below which an indication is required (9 V). Should the supply drop to below 7 V, Dl will cease conducting causing Ql to shut off.
Voltage monitor Circuit Diagram
Its collector voltage will now increase causing Q2 to start conducting via LED1 and its limiting resistor R4.
Sunday, September 7, 2014
Low cost Step down Converter with Wide Input Voltage Range
The schema described here is mostly aimed at development engineers who are looking for an economical step-down converter which offers a wide input volt- age range. As a rule this type of schema employs a step-down converter with integrated switching element. However, by using a more discrete solution it is possible to reduce the total cost of the step- down converter, especially when manufacturing in quantity. The TL5001A is a low-cost PWM controller which is ideal for this project. ![]()
The input voltage range for the step-down converter described here is from 8 V to 30 V, with an output voltage of 5 V and a maximum output current of 1.5 A. When the input voltage is applied the PWM output of IC1 is enabled, taking one end of the voltage divider formed by R1 and R2 to ground potential. The cur-rent through the voltage divider will then be at most 25 mA: this value is obtained by dividing the maximum input voltage (30 V) minus the saturation voltage of the output driver (2 V) by the total resistance of the voltage divider (1.1 kΩ ). T1 and T3 together form an NPN/PNP driver stage to charge the gate capacitance of P-channel MOSFET T2 as quickly as possible, and then, at the turn-off point, discharge it again. The base-emitter junction of T3 goes into a conducting state when the PWM output is active and a voltage is dropped across R2. T3 will then also conduct from collector to emitter and the gate capacitance of T2 will be discharged down to about 800 mV. The P-channel MOSFET will then conduct from drain to source. If the open-collector output of the controller is deactivated, a negligibly small current flows through resistor R2 and the base of T1 will be raised to the input voltage level. The base-emitter junction of T1 will then conduct and the gate capacitance of T2 will be charged up to the input voltage level through the collector and emitter of T1. The P-channel MOSFET will then no longer conduct from drain to source. This driver schema constructed from discrete components is very fast, giving very quick switch-over times. Diodes D2 and D3 provide voltage limiting for the P-channel MOSFET, whose maximum gate-source voltage is 20 V. If the Zener voltage of diode D2 is exceeded it starts to conduct; when the forward voltage of diode D3 is also exceeded, the two diodes together clamp the gate-source voltage to approximately 19 V. The switching frequency is set at approximately 100 kHz, which gives a good compromise between efficiency and component size. Finally, a few notes on component selection. All resistors are 1/16 W, 1 %. Apart from electrolytic C1 all the capacitors are ceramic types. For the two larger values (C2 and C5) the following are used: C2 is a Murata type GRM21BR71C105KA01 ceramic capacitor, 1 µF, 16 V, X7R, 10 %; C5 is a Murata type GRM32ER60J476ME20 ceramic capacitor, 47 µF, 6.3 V, X5R, 10 %. D1 (Fairchild type MBRS340T3) is a 40 V/3 A Schottky diode. Coil L1 is a Würth WE-PD power choke type 744771147, 47 µH, 2.21 A, 75 mΩ. T1 (BC846) and T3 (BC856) are 60 V, 200 mA, 310 mW complementary bipolar transistors from Vishay. The TL5001AID (IC1) is a low-cost PWM controller with an open-collector output from Texas Instruments.
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Author : Dirk Gehrke Copyright : Elektor
Thursday, August 28, 2014
Voltage Controlled Attenuator VC Using FET
Build a Voltage-Controlled Attenuator VC Using FET. Using the schema shown in the schematic diagram below, we can control the low-level audio signals with ±3V variable DC voltage. This attenuator schema uses a field effect transistor (FET) to shunt the signal to ground. The R2 is used to control the output level (the attenuation level), but you can use other source of voltage signal to control the grid of the FET, such as DAC output, just remember that this voltage is a negative going signal (you can use with DAC which uses symmetric power supply system). The minimum output of this schema is when gate bias is zero. When the gate bias is set close to pinchoff value, the schema will produce maximum output with value that equal to input level. Here is the schematic diagram of the schema:
Voltage-Controlled Attenuator VC Using FET Circuit Diagram
Monday, August 25, 2014
12KV High Voltage Generator Wiring diagram Schematic
The hobby schema below uses an unusual method to generate about 12,000 volts with about 5uA of current. Two SCRs form two pulse generator diagram. The two SCRs discharge a 0.047uF a 400v capacitor through a xenon lamp trigger coil at 120 times a second.
12KV High Voltage Generator Circuit Diagram
12KV High Voltage Generator Circuit Diagram
The high voltage pulses produced at the secondary of the trigger coil are rectified using two 6KV damper diodes. The voltage doubler schema at the secondary of the trigger coil charges up two high voltage disc capacitors up to about 12KV. Although this schema can’t produce a lot of current be very careful with it. A 12KV spark can jump about 0.75 of an inch so the electronic schema needs to be carefully wired with lots of space between components.
Source by : Streampowers
Wednesday, August 13, 2014
Low Voltage monitor
This is a schema which can be used to monitor batteries or other electric equipments current problems.Here that current will be indicated through the sound and through the LED.So you all can check your low volt equipments easily.
Parts:
U1 LM339 Voltage comparator IC
D1 1N5233B Zener Diode
D2 LED
R1, R3 1K 1/4W Resistor
R2 5K Pot
BZ1 Piezo Buzzer
MISC Board, wire, socket for IC
Note
# This schema can be operated with 9v to 12v
Saturday, August 9, 2014
Voltage to Current Converter Wiring diagram Schematic
This is a Simple Voltage to Current Converter Circuit Diagram. This is an electronic schema, The current out is Iqut—Vin/R. For negative currents, a PNP can be used and, for better accuracy,-a Darlington pair can be substituted for the transistor. With careful design, this schema can be used to control currents of many amps Unity gain compensation is necessary.
Simple Voltage to Current Converter Circuit Diagram
Friday, August 8, 2014
Voltage Tester for Model Batteries
With a suitable load, the terminal voltage of a NiCd or lithium-ion battery is proportional to the amount of stored energy. This relationship, which is linear over a wide range, can be used to build a simple battery capacity meter.
Voltage Tester for Model Batteries Circuit Image
This model battery tester has two functions: it provides a load for the battery, and at the same time it measures the terminal voltage. In addition, both functions can be switched on or off via a model remote-control receiver, to avoid draining the battery when it is not necessary to make a measurement. The load network, which consists of a BC517 Darlington transistor (T2) and load resistor R11 (15 Ω /5 W), is readily evident. When the load is active, the base of T1 lies practically at ground level. Consequently, T1 conducts and allows one of the LEDs to be illuminated.
Voltage Tester for Model Batteries Circuit Diagram
The thoroughly familiar voltmeter schema, which is based on the LM3914 LED driver, determines which LED is lit. The values of R6 and R7 depend on the type and number of cells in the battery. The objective here is not to measure the entire voltage range from 0 V, but rather to display the portion of the range between the fully charged voltage and the fully discharged voltage. Since a total of ten LEDs are used, the display is very precise. For a NiCd battery with four cells, the scale runs from 4.8 V to 5.5 V when R6 = R7 = 2 kΩ. The measurement scale for a lithium-ion battery with two cells ranges from 7.2 V to 8.0 V if R6 = 2 kΩ and R7 = 1 kΩ.
For remote-control operation, both jumpers should be placed in the upper position (between pin 1 and the middle pin). In this configuration, either a positive or negative signal edge will start the measurement process. A positive edge triggers IC1a, whose output goes High and triggers IC1b. A negative edge has no effect on IC1a, but it triggers IC1b directly. In any case, the load will be activated for the duration of the pulse from monostable IC1b. Use P12 to set the pulse width of IC1a to an adequate value, taking care that it is shorter than the pulse width of IC1b.
If the voltage tester is fitted into a remote-controlled model, you can replace the jumpers with simple wire bridges. However, if you want to use it for other purposes, such as measuring the amount of charge left in a video camera battery, it is recommended to connect double-throw push-button switches in place of JP1 and JP2. The normally closed contact corresponds to the upper jumper position,while the normally open contact corresponds to the lower position.
Parts :
Resistors: R1,R2 = 47kΩ
R3 = 100kΩ
R4 = 500kΩ
R5 = 1kΩ
R6,R7 = see text (1% resistors!)
R8 = 1kΩ5
R9 = 1kΩ2
R10 = 330Ω
R11 = 15Ω 5W
R12 = 15kΩ
P1 = 100kΩ preset
Capacitors:
C1 = 10nF
C2 = 100nF
Semiconductors:
D1-D10 = LED, red, high effi-ciency
T1 = BC557
T2 = BC517
IC1 = 74HC123
IC2 = LM3914AN
Miscellaneous:
PC1,PC2,PC3 = solder pin
JP1,JP2 = jumper or pushbutton
PCB Layout :
Voltage Tester for Model Batteries PCB Layout
Copyright : Elektor
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