Principle The circuit is connected to the power supply The working principle of the voltage regulator chip The moment The working principle of the voltage regulator chip , because the capacitor C has no time to charge, Vc=0v, and the output Vo is high. At the same time, the collector output end (7 pin) is disconnected to the ground, the power supply Vcc charges the capacitor C, the circuit enters a transient state, and then the circuit repeatedly produces a periodic voltage regulator chipPrinciple output pulse. The maintenance time of the two transient states of the multivibrator depends on the parameters of the RC charging and discharging circuits.
The working principle of the three-terminal integrated voltage regulator is introduced by taking the 78L12 series with positive voltage output as an example. In the figure, R11 is determined by the output current grade, and R12 by the output voltage grade. The circuit in Figure 1 is shown in Figure 1. The three-terminal voltage regulator consists of a starting circuit, a reference voltage circuit, a sampling and comparison amplifier circuit, an adjusting circuit and a protection circuit. The following is a brief introduction of each part of the circuit.
Three-terminal stable.
1, J1 is Line input 5V, the two 104 capacitors are filter capacitors, the pins are grounded respectively, mainly filter out high-frequency ripple, prevent self-excited oscillation; 47UF and 100UF are filter capacitors, which mainly filter out low-frequency ripple. R1 acts as a current limiting function to protect voltage regulator diode D2. When the input voltage and output load current change, R1 passes through the change of its own voltage drop.
2, uh... What is the principle to say, relying on the integrated circuit AS2815 to step down the input voltage to the rated 3V output... AS2815 is a low pressure differentialLinear Voltage regulator (LDO), maximum current 5A.
3, v to 3v circuit design diagram: three-terminal voltage regulator: three-terminal voltage regulator, there are two main kinds, one output voltage is fixed, called fixed output three-terminal voltage regulator, the other output voltage is adjustable, called adjustable output three-terminal voltage regulator, the basic principle is the same, all use series type voltage regulator circuit.
/79 series is a three-terminal regulator: the 78 series has a positive output.
Fixed integrated voltage regulator An integrated voltage regulator is an integrated circuit that changes an unstable DC voltage into a stable DC voltage. The integrated voltage regulator has been widely used in various power supply circuits because of its advantages of high voltage stability, stable and reliable operation, simple peripheral circuit, small size and light weight.
Hello: -- ★78 series, 79 series voltage regulator integrated circuit, belongs to the fixed output voltage regulator: the voltage regulator output is fixed. -- ★ The last two digits of the regulated integrated circuit model are the regulated output voltage value.
Input and output pressure difference can not be too large, too large, the conversion efficiency is rapidly reduced, and easy to breakdown damage; The output current cannot be too large, 5A is its limit. Large current output, the size of the heat sink should be large enough, otherwise it will lead to high temperature protection or thermal breakdown; Input and output pressure difference can not be too small, the size efficiency is very poor.
1. They work in the same way. It's deep negative feedback. There is a reference voltage source inside, through the voltage comparator to control the triode base, the output voltage is high, the base current is reduced, the triode conduction capacity is reduced, the higher voltage loss on the triode, into heat energy.
2, the working principle of the three-end voltage regulator circuit: is the current source type voltage regulator circuit, by adjusting the output current to ensure the output voltage, the feedback is the voltage, the reference is also the voltage, through the internal circuit into the feedback current and the reference bypass current, the difference and go to the bypass internal current source to make the outputThe current meets the stability of the terminal voltage.
3, principle: when the input voltage or load changes, the control circuit for sampling, comparison, amplification, and then drive the servo motor rotation, so that the regulator carbon brush position change, by automatically adjusting the coil turn ratio, so as to maintain the stability of the output voltage. When the regulated power supply is powered on, do not disassemble the regulated power supply or pull the input and output cable of the regulated power supply at will to prevent electric shock or other electrical safety accidents.
4, the output voltage is not adjustable, known as a fixed voltage regulator. Output voltage: 8V ~ 2V. Pin 1-Vin (input 5-18V),Pin 2-GND, pin 3-Vout (output 5V). The LM317 is an adjustable three-end voltage regulator capable of delivering over 5 amps in the output voltage range 2V to 37V, making it very easy to use. Foot 1- Adjustment, foot 2-Vout, foot 3-Vin.
5, is a three-terminal voltage regulator, it can stably adjust the input voltage to 5V output. Its working principle is to regulate the output voltage by controlling the current flow through the regulating circuit. The 7805 circuit contains a feedback circuit that compares the output voltage to a reference voltage.If the output voltage is higher than the reference voltage, the feedback circuit reduces the current flowing through the regulator circuit, thereby lowering the output voltage.
1, is a voltage regulator power chip, its working principle is to maintain the stability of the output voltage by controlling the output current. When the output voltage is reduced, the 7805 will increase the output current to increase the output voltage. When the output voltage rises, the 7805 will reduce the output current to reduce the output voltage. This kind of adjustment makesThe 7805 keeps the output voltage stable over the input voltage fluctuation range.
2, is a three-terminal voltage regulator, it can stably adjust the input voltage to 5V output. Its working principle is to regulate the output voltage by controlling the current flow through the regulating circuit. The 7805 circuit contains a feedback circuit that compares the output voltage to a reference voltage. If the output voltage is higher than the reference voltage, the feedback circuit reduces the current flowing through the regulator circuit, thereby lowering the output voltage.
3, is a linear voltage regulator, its working principle is to use a toneA current-saving transistor (usually an NPN transistor) to control the output voltage of a regulator circuit. Its input voltage may change with time or load, and the regulating current transistor will adjust the output voltage according to the difference between the input voltage and the output voltage to maintain a stable output voltage.
4, the working principle of the three-terminal voltage regulator: voltage regulator VD1 is connected in series between the 78XX regulator 2 pin and the ground, which can make the output voltage Uo be improved to a certain extent, and the output voltage Uo is the sum of the output voltage of the 78XX regulator and the voltage regulator diode VC1. VD2 is the outputThe protection diode, once the output voltage is lower than the VD1 voltage regulator value, the VD2 is switched on and the output current is bypassed to protect the 7805 voltage regulator output stage from damage.
5, the most used in electronic manufacturing is a three-terminal fixed output regulator. Integrated regulators can be divided into series adjustment type, parallel adjustment type and switching type regulator three categories.