Showing posts with label Adjustable. Show all posts
Showing posts with label Adjustable. Show all posts
Friday, October 24, 2014
Adjustable Symmetrical Power Supply Using LM317 and LM337
The circuit was designed to provide an adjustment with a power supply that is symmetrically designed while providing a voltage range of 1.25V to 30V at 1A current. LM317 – an adjustable 3-terminal positive voltage regulator capable of supplying in excess of 1.5A over an output voltage range of 1.2V to 37V and requires only two external resistors to set the output voltage due to its internal current limiting, thermal shutdown and safe area compensation, making it essentially blow-out proof LM337 – an adjustable 3-terminal positive voltage regulator capable of supplying in excess of 5A used as battery chargers, constant current regulators, and adjustable power supplies due to its features such as protected output from short circuit, product enhancement tested, current limit constant with temperature, guaranteed thermal regulation, adjustable output down to 1.2V, guaranteed 5A, and guaranteed 7A peak output current.
The circuit will serve as a voltage converter with an input voltage of 35 V to produce an output voltage of 1.25 V to 30 V. The positive voltage is being handled by LM317 IC while the negative voltage is handled by LM337. The circuit can provide an output current of 1 A. During the production of 1 A current, the regulator is dissipating too much heat and without the presence of a heatsink, the regulator may get damaged.
Using these types of regulators provide features such as low noise and low price in the market. It can be made operational even with few components used. The only disadvantage that it will impose is the poor conversion efficiency. With the output of 35 V to 5 V, the efficient ratio of the output power with the input power is less than 42%. This is the reason why the switching regulator became cheap recently although the number of external components to be connected is minimally increased. These regulators will work with better efficiency when used in case where current is more than 1A for more than 15 V and 0.4 A for less than 15 V from the power supply. Each regulator is adjusted for single positive and negative voltage output using the 10K ohms potentiometers RV1 & RV2. For dual outputs, a dual connected potentiometer RV3 is made to operate by switch S1. The visual indication on the voltmeter V1 is shown using the switch S2.
Using these types of regulators provide features such as low noise and low price in the market. It can be made operational even with few components used. The only disadvantage that it will impose is the poor conversion efficiency. With the output of 35 V to 5 V, the efficient ratio of the output power with the input power is less than 42%. This is the reason why the switching regulator became cheap recently although the number of external components to be connected is minimally increased. These regulators will work with better efficiency when used in case where current is more than 1A for more than 15 V and 0.4 A for less than 15 V from the power supply. Each regulator is adjusted for single positive and negative voltage output using the 10K ohms potentiometers RV1 & RV2. For dual outputs, a dual connected potentiometer RV3 is made to operate by switch S1. The visual indication on the voltmeter V1 is shown using the switch S2.
- R1-2=270ohms
- R3-4=2.2Kohms
- R5-6=10Kohms
- C1-5=100uF/63V
- C2-4=100nF/100V
- C3-8=10uF/25V
- C6-10=100uF/63V
- C7-9=100nF/100V
- RV1-2=10Kohms Lin.
- RV3=2X10Kohms Lin.
- IC 1=LM 317T
- IC 2=LM 337T
- D1-2=1N4001
- D3-4=1N4001
- L1-2=LED 3mm
- F1-2=1A slow Blow Fuse
- S1-2=2X ON-ON SW
- V1=0-30V DC Voltmeter
The adjustable symmetrical power supply is suitable to be used in audio amplifiers, microphone amplifiers, op-amp applications, impedance converters and other devices that require regulated positive and negative DC supply, since the output current is 1 A.
Monday, October 20, 2014
Adjustable Voltage and Variable Current Limiter Circuit Diagram
This Mini Voltage Source with Adjustable Current Limit variable is very simple and efficient, ideal for small shippers or circuits that require a current limiter with adjustable voltage that this circuit can vary from a few mA up to 2 A and voltage 1.225v up to 12V or more, depending on the power supply.
Once the current reaches the limit set by the 100R resistor, transistor BC547 begins to act on the voltage regulator in the Adj pin and the output voltage starts to decrease. If the output is shorted, the output voltage will reduce to almost zero, as a kind of protection.
Adjustable Voltage and Variable Current Limiter Circuit Diagram
Adjustable Voltage and Variable Current Limiter Circuit Diagram
Saturday, October 4, 2014
Power Supply Adjustable 0 30V
The aboriginal affair you charge accept in your workshop/lab is ability supply. In experimenting abounding new cyberbanking ambit design, it is easier if you accept a adjustable adjustable ability supply. Here is an adjustable 0-30 volts ability accumulation design. The ambit schematic diagram is apparent below.
The amount of the ambit is 723 voltage regulator chip circuit. A Darlington brace Q2 Q3 addition the accepted to accord 1A output. The minimum voltage acclimation for this regulator IC is 2 volts aloft V-. Aught volt is accomplished by bartering the V- with a voltage beneath -2V, so the achievement can be adapted to zero. The abrogating accumulation is provided by the apparatus about D3 and D4, counterbalanced by 5.1 Zener diode.
The capricious resistor R3 is acclimated to set the accepted limiter, so your ability accumulation will be save alike back you abbreviate its achievement to ground. To set the aught point, about-face the R11 potentiometer to minimum (counter clockwise) and acclimatize the R12 trimmer potentiometer until the achievement is zero. After this setting, axis the R11 potentiometer to the best will accord about 30V output. If at the best position the achievement is abate than 30V, it’s acceptable acquired by the apparatus tolerance, you can lower the R10 value. Make abiding you use beyond clue for arena affiliation on the PCB, and accommodate acceptable calefaction bore for Q3.
The amount of the ambit is 723 voltage regulator chip circuit. A Darlington brace Q2 Q3 addition the accepted to accord 1A output. The minimum voltage acclimation for this regulator IC is 2 volts aloft V-. Aught volt is accomplished by bartering the V- with a voltage beneath -2V, so the achievement can be adapted to zero. The abrogating accumulation is provided by the apparatus about D3 and D4, counterbalanced by 5.1 Zener diode.
The capricious resistor R3 is acclimated to set the accepted limiter, so your ability accumulation will be save alike back you abbreviate its achievement to ground. To set the aught point, about-face the R11 potentiometer to minimum (counter clockwise) and acclimatize the R12 trimmer potentiometer until the achievement is zero. After this setting, axis the R11 potentiometer to the best will accord about 30V output. If at the best position the achievement is abate than 30V, it’s acceptable acquired by the apparatus tolerance, you can lower the R10 value. Make abiding you use beyond clue for arena affiliation on the PCB, and accommodate acceptable calefaction bore for Q3.
The parts list:
| Item | Quantity | Reference | Part |
|---|---|---|---|
| 1 | 1 | C1 | 470uF/63V |
| 2 | 1 | C2 | 470uF/40V |
| 3 | 1 | C3 | 2200uF/63V |
| 4 | 1 | C4 | 100uF/35V |
| 5 | 1 | C5 | 1nF |
| 6 | 1 | D1 | 5V1 |
| 7 | 1 | D2 | 33V |
| 8 | 4 | D3,D4,D5,D6 | 1N4001 |
| 9 | 1 | D7 | DIODE BRIDGE |
| 10 | 1 | D8 | LED |
| 11 | 1 | F1 | 1.5A |
| 12 | 1 | J1 | PLUG AC MALE |
| 13 | 1 | Q1 | BC557B |
| 14 | 1 | Q2 | BC141 |
| 15 | 1 | Q3 | Q2N3055 |
| 16 | 1 | R1 | 560R |
| 17 | 1 | R2 | 2k2/1W |
| 18 | 2 | R3,R5 | 2k2 |
| 19 | 2 | R10,R6 | 1k2 |
| 20 | 1 | R8 | 100R |
| 21 | 1 | R9 | 0R33/1W |
| 22 | 1 | R11 | POT 10k |
| 23 | 1 | R12 | VR 10k |
| 24 | 1 | R13 | VR 1k |
| 25 | 1 | T1 | 30V 1A |
| 26 | 1 | U1 | LM723 |
Tuesday, September 23, 2014
Adjustable voltage output control by 2SC458
This again the one circuit that use in fining value output voltage, for apply give straight with the requirement of load be the circuit that is simple and have no result temperature way of the joint junction of transistor. Vout control 0V-30V at 0.1A
The principle works be transistor Q1 2SC458 that built model common-emitter amplifier, which perform fine decrease input voltage get down then heal volt that give may but at collector voltage compare with ground. Which get from the combination of voltage at base – emitter pin (0.6V) with VZener diode (6.2V) already fine the value of a resister can fine the value VR1 help transistor part Q2 2SC458 perform be compared as power supply current source and current that fixed. By current at flow come in the way base pin of Q2 and when Q2 bias current. That already Voltage output get, with fining that a resister VR1 during 5.8V-15.8V. By have R3 and C1 perform be RC Filter caution. This circuit power current source get 100mA topmost should apply to load that use current low.
s:www.eleccircuit.com
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The principle works be transistor Q1 2SC458 that built model common-emitter amplifier, which perform fine decrease input voltage get down then heal volt that give may but at collector voltage compare with ground. Which get from the combination of voltage at base – emitter pin (0.6V) with VZener diode (6.2V) already fine the value of a resister can fine the value VR1 help transistor part Q2 2SC458 perform be compared as power supply current source and current that fixed. By current at flow come in the way base pin of Q2 and when Q2 bias current. That already Voltage output get, with fining that a resister VR1 during 5.8V-15.8V. By have R3 and C1 perform be RC Filter caution. This circuit power current source get 100mA topmost should apply to load that use current low.
s:www.eleccircuit.com
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