Showing posts with label voltage. Show all posts
Showing posts with label voltage. Show all posts
Monday, December 16, 2013
Simple Positive And Negative Voltage Power Supply Circuit Diagram
This Simple Positive And Negative Voltage Power Supply Circuit Diagram provides a precision voltage source that can be adjusted through zero to positive and negative voltages, which eliminates reversing connections on the power supply. Also, it is possible to get exactly 0 V, without some offset. As to how this circuit works, first consider the -1 V/V to +1 V/V linear gain-control amp (see the figure). A Burr-Brown INA105 difference amp is used in a unity-gain inverting amp configuration.
Positive And Negative Voltage Power Supply Circuit Diagram
A potentiometer is connected between the input and ground. The pot`s slider is connected to the noninverting input of the unity-gain amp; this input is typically connected to ground. With the slider at the bottom of the pot, the circuit is a normal-precision unity-gain inverting amp with a gain of -1.0 V/V ± 0.01% maximum.
With the slider at the top of the pot, the circuit is a normal-precision voltage follower with a gain of ± 1.0 V/V ± 0.001% maximum. With the slider in the center, there`s equal positive and negative gain for a net gain of 0 V/V. The accuracy between the top and the bottom will usually be limited by the accuracy of the pot.
Source Simple Positive And Negative Voltage Power Supply Circuit Diagram
Source Simple Positive And Negative Voltage Power Supply Circuit Diagram
Thursday, August 15, 2013
High Voltage Regulator Circuit Diagram
The High Voltage Regulator Circuit Diagram delivers 100-V at 100 mA and withstands shorts to ground. Even at 100 V output, the LT317A functions in the normal mode, maintaining 1.2 V between its output and adjustment pin. Under these conditions, the 30-V zener is off and Ql conducts. When an output short occurs, the zener conducts, forcing Q1`s base to 30 V.
This causes Q1`s emitter to clamp 2 VnEs below Vz. well within the V.w VouT rating of the regulator. Under these conditions, Q1, a high-voltage device, sustains 90 V-VcE at whatever current the transformer specified saturates at 130 mA, while Q1 safely dissipates 12 W. If Q1 and the LT317 A are thermally coupled, the regulator will soon go into thermal shutdown and oscillation will commence.
This action will continue, protecting the load and the regulator as long as the output remains shorted. The 500-pF capacitor and the 10 0/0.02 11F damper aid transient response and the diodes provide safe discharge paths for the capacitors.
High Voltage Regulator Circuit Diagram
Wednesday, August 7, 2013
How to Build a Photodiode current to voltage converter
The Photodiode current-to-voltage converter circuit uses three CA3130 BiMOS op amps in an application sensitive to sub-picoampere input currents. The circuit provides a ground-referenced output voltage proportional to input current flowing through the photo-diode.
Photodiode current-to-voltage converter circuit
Friday, August 2, 2013
Simple Up Controlled Negative Voltage Converter Circuit Diagram
This Simple Up-Controlled Negative Voltage Converter Circuit Diagram was used to produce a variable negative voltage for contrast control of an LCD display. A 74F374 generates a square wave that is ac coupled to a rectifier and load. By using the uP clock and data from the processor bus, and properly timed load signal, the dc level generated can be controlled by the uP.
Simple Up-Controlled Negative Voltage Converter Circuit Diagram
Monday, May 13, 2013
Battery Voltage Indicator Circuit
Connecting this circuit to the battery of your vehicle, you will always know at a glance the approximate voltage available. An indication of battery voltage is useful to the motorist for monitoring the batterys capacity to deliver current, and as a check on the efficiency of the dynamo or alternator. Threshold voltages of the Leds are set by means of two Zener Diodes (D6 & D10) plus two further Diodes wired in series (D4, D5 and D8, D9 respectively) adding a step of about 1.3V to the nominal Zener voltage.
Parts:
R1 = 1k
R2 = 100K
R3 = 1k
R4 = 3.3K
R5 = 3.3K
R6 = 1k
R7 = 3.3K
R8 = 3.3K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = Red Led
D2 = Amber Led
D3 = 1N4148
D4 = 1N4148
D5 = 1N4148
D6 = BZX79C10
D7 = Green Led
D8 = 1N4148
D9 = 1N4148
D10 = BZX79C12
Notes:
* Red LED D1 is on when battery voltage is 11.5V or less. This indicates a low battery charge. * Amber LED D2 is on when battery voltage is comprised in the 11.5 - 13.5V range. This indicates that the battery is good if the motor is off. When motor is running, this indicates no charge from dynamo or alternator. * Green LED D7 is on when battery voltage is 13.5V or more. This indicates a normal condition when motor is running and dynamo or alternator is charging.
Continue Read...
Parts:
R1 = 1k
R2 = 100K
R3 = 1k
R4 = 3.3K
R5 = 3.3K
R6 = 1k
R7 = 3.3K
R8 = 3.3K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = Red Led
D2 = Amber Led
D3 = 1N4148
D4 = 1N4148
D5 = 1N4148
D6 = BZX79C10
D7 = Green Led
D8 = 1N4148
D9 = 1N4148
D10 = BZX79C12
Notes:
* Red LED D1 is on when battery voltage is 11.5V or less. This indicates a low battery charge. * Amber LED D2 is on when battery voltage is comprised in the 11.5 - 13.5V range. This indicates that the battery is good if the motor is off. When motor is running, this indicates no charge from dynamo or alternator. * Green LED D7 is on when battery voltage is 13.5V or more. This indicates a normal condition when motor is running and dynamo or alternator is charging.
Friday, May 3, 2013
Low Voltage High Current Time Delay Circuit diagram
In this circuit a LM339 quad voltage comparator is used to generate a time delay and control a high current output at low voltage. Approximatey 5 amps of current can be obtained using a couple fresh alkaline D batteries. Three of the comparators are wired in parallel to drive a medium power PNP transistor (2N2905 or similar) which in turn drives a high current NPN transistor (TIP35 or similar
The 4th comparator is used to generate a time delay after the normally closed switch is opened. Two resistors (36K and 62K) are used as a voltage divider which applies about two-thirds of the battery voltage to the (+) comparator input, or about 2 volts. The delay time after the switch is opened will be around one time constant using a 50uF capacitor and 100K variable resistor, or about (50u * 100K) = 5 seconds. The time can be reduced by adjusting the resistor to a lower value or using a smaller capacitor. Longer times can be obtained with a larger resistor or capacitor. To operate the circuit on higher voltages, the 10 ohm resistor should be increased proportionally, (4.5 volts = 15 ohms).
Monday, April 8, 2013
High And Low Voltage Cut Off Circuit
This is a design for protection voltage. This circuit is called as high and low voltage cut off. The circuit is using time delay for cut off the voltage. This is a low cost and reliable circuit for protecting such equipments from damages. This is the figure of the circuit.
Whenever the power line is switched on it gets connected to the appliance only after a delay of a fixed time. If there is hi/low fluctuations beyond sets limits the appliance get disconnected. The system tries to connect the power back after the specific time delay, the delay being counted from the time of disconnection. If the power down time (time for which the voltage is beyond limits) is less than the delay time, the power resumes after the delay: If it is equal or more, then the power resumes directly. This circuit is using op-amp 741 and 555 IC for control the operation.
The complete circuit is consisting of various stages. They are: - Dual rail power supply, Reference voltage source, Voltage comparators for hi/low cut offs, Time delay stage and Relay driver stage. Under normal operating conditions i.e. when the input voltage is between maximum and minimum limit the output from the both the comparators are low. The transistor Q1 is OFF and the relay is in de-energized (pole connected to N/C pin) state and the output is obtained. When the input voltage is below or above the limits set by the pre-sets R8 or R9, the output of the Op-Amps goes either low or high and diodes D1 or D2 would be forward biased depending on the situation. Transistor Q1 switches ON and the flow of current from collector to emitter energizes the relay and the output is cutoff.
Whenever the power line is switched on it gets connected to the appliance only after a delay of a fixed time. If there is hi/low fluctuations beyond sets limits the appliance get disconnected. The system tries to connect the power back after the specific time delay, the delay being counted from the time of disconnection. If the power down time (time for which the voltage is beyond limits) is less than the delay time, the power resumes after the delay: If it is equal or more, then the power resumes directly. This circuit is using op-amp 741 and 555 IC for control the operation.
The complete circuit is consisting of various stages. They are: - Dual rail power supply, Reference voltage source, Voltage comparators for hi/low cut offs, Time delay stage and Relay driver stage. Under normal operating conditions i.e. when the input voltage is between maximum and minimum limit the output from the both the comparators are low. The transistor Q1 is OFF and the relay is in de-energized (pole connected to N/C pin) state and the output is obtained. When the input voltage is below or above the limits set by the pre-sets R8 or R9, the output of the Op-Amps goes either low or high and diodes D1 or D2 would be forward biased depending on the situation. Transistor Q1 switches ON and the flow of current from collector to emitter energizes the relay and the output is cutoff.
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