268 results about "Voltage clamp" patented technology

The invention discloses a negative voltage clamping circuit and method. The negative voltage clamping circuit comprises a current mirroring module which is used for providing a reference current Iref and generating a corresponding reference current according to a preset current proportion mirroring; the voltage detection module is connected with the current mirror module and the negative voltage input end of the chip and is used for detecting the voltage VS of the negative voltage input end; and the clamping control module is connected with the current mirroring module and the voltage detection module, and the clamping control module is configured to be switched on when the voltage VS of the negative voltage input end exceeds a preset clamping threshold value and clamp the voltage VS of the negative voltage input end within a preset range. According to the negative voltage clamping circuit, the change of the negative voltage input end can be monitored in real time, it is ensured that the clamping control module responds rapidly when the voltage exceeds a threshold value, the negative voltage is limited within a safe range, circuit damage or performance reduction caused by too low voltage is avoided, and therefore the stability and reliability of a chip are improved.

In one example, a circuit includes a first transistor having a first terminal coupled to a first supply voltage source, a second transistor coupled between a second terminal of the first transistor and a ground terminal, and a voltage clamp circuit coupled between the first supply voltage source and the ground terminal. The circuit may further include a first switch coupled between a control terminal of the first transistor and a second supply voltage source, the first switch having a control terminal coupled to the second terminal of the first transistor, a second switch coupled between a control terminal of the second transistor and the second supply voltage source, the second switch having a control terminal coupled to the ground terminal, and a filter coupled between the control terminal of the second transistor and the ground terminal.

The invention relates to the technical field of off-grid renewable energy hydrogen production, and discloses an off-grid alkaline hydrogen production system and a power adaptive distribution and safety control method thereof, the off-grid alkaline hydrogen production system comprises a renewable energy power supply unit, a parallel electrolytic cell module, a gas-liquid treatment system and a main controller; in the Faraday hydrogen production mode, the bubble volume is compressed by adjusting the operation pressure so as to modulate the impedance characteristic of the electrolytic cell, and the energy efficiency is improved in cooperation with current control; and in the non-Faraday polarization hot standby mode, the voltage of the rectifier cabinet is controlled to be clamped to a non-gassing polarization interval, and liquid level plugging is constructed in the U-shaped communicating pipeline according to the fluid statics principle. The system is further provided with a transient buffering strategy based on the pneumatic capacity, and pressure attenuation is delayed through the gas dead zone volume when power is suddenly reduced. The problems of hydrogen production efficiency optimization, low-power safe hot standby and mechanical protection under wide power fluctuation are effectively solved.

The invention relates to the technical field of isolation driving chips, and provides a common-mode rejection circuit, an isolation transmission circuit and a motor driving circuit. The common-mode rejection circuit comprises a first transistor, a second transistor, a third transistor, a fourth transistor, a first resistor, a second resistor, a first clamping circuit and a second clamping circuit. The first clamping circuit is coupled between the power supply voltage of the receiver and a common node of the first end of the first transistor and the first end of the second transistor, and is used for clamping the voltage on the first common node; the second clamping circuit is coupled between a common node of the first end of the third transistor and the first end of the fourth transistor and the reference ground of the receiver, and is used for clamping the voltage on a second common node. According to the invention, the common-mode transient interference can be effectively suppressed in the isolation transmission circuit, and the system reliability is improved.

A short-circuit protection circuit of a half-bridge driving chip relates to the field of short-circuit protection and integrated circuit design, and comprises a pre-driving module for generating a high-side signal and a low-side signal; the half-bridge module is driven, a high-side MOS receives a high-side signal, and a low-side MOS receives a low-side signal; the gate source hardware clamping module is used for carrying out voltage clamping on the high-side MOS when over-current of the over-ground short circuit of the high-side MOS is detected; the phase voltage short-circuit protection module is used for controlling the overcurrent time when the high-side MOS short circuit is over-current, and sending a fault signal to the logic module when detecting that the high / low-side MOS short circuit is over-current; the bus over-current protection module is used for sending a fault signal to the logic module when bus over-current is detected; and the logic module judges whether the short-circuit protection circuit enters a protection state according to the fault signal. According to the invention, the response speed and the protection mechanism are intelligently switched in real time in different overcurrent fault scenes through the three-stage protection circuit, and the circuit has the characteristics of high sensitivity, fast response speed and strong anti-interference capability.

Provided is a power source control device for a DC / DC converter including a high-side transistor, a low-side transistor, and an inductor, the power source control device including a first error amplifier configured to receive a first reference voltage and a feedback voltage based on an output voltage of the DC / DC converter, a second error amplifier configured to receive an output of the first error amplifier and a signal indicating information regarding a current flowing through the inductor, a first comparator configured to receive an output of the second error amplifier and a ramp voltage, a switching control unit configured to perform switching control of the high-side transistor and the low-side transistor according to an output of the first comparator, and a clamp circuit configured to clamp a second amplifier output voltage outputted from the second error amplifier, to a predetermined clamp voltage.

The application provides a driving method of an inverter bridge, a driving circuit, a servo driver and a motor device. In the driving method of the inverter bridge, voltage vector output time and dead time are set, so that a power switch tube of a jth bridge arm is kept in a conduction state in two adjacent voltage vector output times before switching, the power switch tubes kept in the conduction state are changed in turn and staggeredly, in each dead time, two other power switch tubes kept in the conduction state in a previous voltage vector output time are switched off, the corresponding switching bridge arm and winding complete resonance work, the end voltage of the power switch tube to be turned on is clamped to zero potential, zero voltage conduction is realized, a soft switching mode is formed, and the switching loss is reduced and the power conversion efficiency is improved.

This disclosure presents an embodiment of a power supply device for a submarine data center. One specific embodiment of the power supply device includes a pre-stage voltage regulator / conversion component, a post-stage DC-DC converter component, and a combined protection circuit. The pre-stage voltage regulator / conversion component includes several parallel single-group voltage regulator branches, each branch connected in series with a varistor and a color-coded resistor. A thin-film capacitor is connected in parallel to the output terminal of the pre-stage voltage regulator / conversion component. The post-stage DC-DC converter component, electrically connected to the pre-stage voltage regulator / conversion component, includes at least two sets of full-bridge DC synchronous rectifier circuits. The combined protection circuit includes a pre-stage combined protection circuit, a post-stage active voltage clamping circuit connected in parallel to the output side of the post-stage DC-DC converter component, and a rectifier diode bridge connected between the constant current input port and the pre-stage voltage regulator / conversion component. The pre-stage combined protection circuit is connected in series to the input side of the rectifier diode bridge. By connecting multiple voltage regulator branches in parallel and combining them with the combined protection circuit, ripple is reduced. This embodiment can improve the power supply stability of the power supply device.

The invention discloses a pulse wave signal detection-oriented transimpedance amplifier circuit with input voltage clamping and current offset functions, and relates to the technical field of integrated circuit design, the pulse wave signal detection-oriented transimpedance amplifier circuit comprises a pseudo-differential structure, a current offset module and a photosensitive diode, the pseudo-differential structure is composed of two independent operational amplifiers with double-end input and single-end output, the trans-impedance amplifier of a pseudo-differential structure composed of two independent operational amplifiers with double-end input and single-end output is used, the same voltage is connected to the same-direction input end of the trans-impedance amplifier, voltage clamping is carried out on double-end input, the differential mode precision and low-frequency stability of an input virtual site are improved, differential mode imbalance and flicker noise caused by operational amplifier mismatch are eliminated, and the stability of the trans-impedance amplifier is improved. The dynamic range of the pulse wave detection system is improved, and the pulse wave detection system has the advantages of high-precision and wide-range ambient light suppression effect, high circuit reliability, low circuit complexity, easy implementation, high loop stability, small area and low power consumption.

The invention relates to the technical field of circuit design, in particular to a cascade cross array, a data processing method and electronic equipment, the array comprises at least one first row line, at least one second row line and at least one column line, and memristive devices are arranged at cross nodes of the first row line and the second row line and the column line; the voltage input module comprises at least one output end, the output end is connected with the first row line, and the output end applies input voltage to the first row line; a trans-impedance amplifier and an analog-to-digital converter are arranged on the second row line, the trans-impedance amplifier is used for clamping the voltage of the second row line to 0V and converting the current of the second row line into voltage, and the analog-to-digital converter outputs the voltage of the trans-impedance amplifier. Therefore, the problems of high power consumption, high delay, incapability of introducing nonlinear transformation in calculation and the like when a voltage input module, an analog-to-digital converter and a trans-impedance amplifier are used for many times are solved.

The utility model provides a lightning protection filter circuit, a lightning protection filter system and electronic equipment. The lightning protection filter circuit comprises a first power line, a second power line and at least one lightning protection device, a first inductor is arranged on the first power line; the at least one lightning protection device comprises a first lightning protection device, one end of the first lightning protection device is connected with the first power line, and the other end is connected with the second power line; the first power line is provided with a first input end for inputting lightning signals, and one end of the first lightning protection device is connected between the first input end and the first inductor; according to the invention, the first lightning protection device can discharge current and clamp voltage in a protection voltage interval; however, since the first lightning protection device has a certain starting time, when a lightning signal invades from the first input end, the first inductor can generate a directional electromotive force and hinder current from passing, so that a certain lightning protection effect is achieved within the starting time of the first lightning protection device, and the lightning protection effect of the lightning protection filter circuit is improved.

The utility model discloses a passive adjustable voltage clamping circuit with a temperature protection function, which comprises an input positive end IN +, an input negative end IN-, a diode D1, a diode D2, a diode D3, a triode Q1, a field effect transistor Q2, a triode Q3, a controllable precise voltage stabilizing source N1, a temperature sensor RT1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7 and a slide rheostat R8, the input positive end IN + and the input negative end IN-serve as input power sources, the clamping circuit works passively and can bear very high power, and the bearing power depends on the peak power of the field efficiency tube; the clamping voltage is adjustable, the voltage precision is high, the error is controlled below 1%, the field effect transistor Q2 has an over-temperature protection function, the circuit is prevented from being damaged due to thermal breakdown when external high voltage lasts for a long time, the circuit is simple, the circuit is composed of discrete components, the cost is low, implementation is easy, and the cost performance is high.

Discharge the charge that requires discharge in the inverter device. [Solution] The inverter device comprises an inverter circuit and an inverter control unit. The inverter circuit comprises a DC terminal pair consisting of a first DC terminal and a second DC terminal, an AC terminal pair consisting of a plurality of AC terminals, a first capacitor and a second capacitor connected in series between the first DC terminal and the second DC terminal, and a plurality of switch elements connected between the DC terminal pair and the AC terminal pair in a predetermined connection pattern, each being made of semiconductors and having a parasitic diode. When the inverter control unit detects an interruption in the DC power input from the DC terminal pair, it controls the plurality of switch elements to turn on and off, clamping the voltage of the first capacitor with the reverse voltage of the parasitic diode of the switched element that is turned off, and clamping the voltage of the second capacitor with the reverse voltage of the parasitic diode of the switched element that is turned off.

The application provides a low-power bandgap reference circuit, a chip and a reference voltage generation method, and solves the problems of high power consumption and the need to use an operational amplifier and a resistor in the prior art bandgap reference, and comprises the following components connected in series: a positive temperature coefficient module comprising a first transistor, a second transistor and a first MOS tube, a difference between base-emitter voltages of the first transistor and the second transistor generating a positive temperature coefficient voltage on the first MOS tube; a clamping module comprising a first clamping MOS tube and a second clamping MOS tube, the clamping module being used to provide equal first clamping voltage and second clamping voltage; a negative temperature coefficient module comprising a first MOS tube and a second MOS tube, threshold voltages of the first MOS tube and the second MOS tube serving as a negative temperature coefficient voltage; a current mirror module proportionally copying a current of a branch in which the first transistor is located to a branch in which the negative temperature coefficient module is located and a branch in which the second transistor is located, and the negative temperature coefficient voltage and the positive temperature coefficient voltage being added together to serve as a reference voltage.

The application provides a method and device for improving the rated current breaking times of a direct-current solid-state circuit breaker and application thereof, and aims at the problem that the performance of an existing direct-current solid-state circuit breaker is degraded after multiple current impacts on a voltage-dependent resistor, the junction temperature of a power device is difficult to measure, and the breaking times are limited due to over-temperature damage, the application comprises a junction temperature prediction module based on a physical information neural network, an auxiliary energy absorption module and a power device voltage clamping module. The junction temperature prediction module accurately predicts the junction temperature of the power device in real time by fusing a physical thermal model and a neural network. The voltage clamping module suppresses the turn-off overvoltage. The auxiliary energy absorption module is started when the junction temperature is close to the limit, and absorbs the remaining energy. The design reasonably allocates the turn-off energy, reduces the impact times and intensity of the voltage-dependent resistor, significantly improves the service life (such as about 10 times under the impact of 200 A), and further greatly improves the rated breaking times of the solid-state circuit breaker, and is low in cost, high in reliability, and suitable for scenes such as a direct-current power grid.

The embodiment of the present application provides a wide voltage range voltage comparison circuit and a wide voltage range voltage processing circuit, the wide voltage range voltage comparison circuit comprises: an input voltage resistance module, which is used for receiving a first voltage and a second voltage, and converting the first voltage and the second voltage into a third voltage and a fourth voltage; a clamping voltage resistance module, which is used for receiving the third voltage and the fourth voltage, and obtaining voltage resistance protection through clamping when the accepted voltage is a high voltage domain, and outputting a first current and a second current; a first mirroring module, which is used for performing mirroring processing on the first current to obtain a third current; a second mirroring module, which is used for performing mirroring processing on the second current to obtain a fourth current; and an inverse output module, which is used for outputting a high or low potential according to the size of the third current and the fourth current. The first mirroring module, the second mirroring module and the input voltage resistance module improve the voltage output range and can amplify the current, and thus the wide range voltage signal comparison is realized.

The invention discloses a method, system and medium for a voltage clamping unit in a chip circuit, and belongs to the technical field of chip circuit protection, and the method comprises the steps: obtaining a maximum allowable voltage deviation window and a maximum allowable voltage rise rate of a target input / output pin of a chip, and constructing a target clamping characteristic parameter set; selecting a clamp sub-model based on the parameter set; adjusting capacitance matching unit parameters according to the equivalent input capacitance of the target pin by combining a support vector regression algorithm with a genetic algorithm; connecting a clamping model and injecting a test voltage waveform, and extracting clamping response time and clamping voltage to construct feedback characteristics; a mathematical model between the clamping response time and the delay gate series is generated through a symbol regression algorithm, and a control delay unit structure is corrected; according to the method, closed-loop adaptive adjustment of clamping parameters is realized, the transient interference suppression capability and clamping precision of the chip under high-frequency and low-voltage conditions are improved, and the method has good reliability and expandability.

Power switching circuitry is provided that includes a power switch having a first terminal coupled to a first power domain and having a second terminal coupled to a second power domain, a diode coupled between the first and second terminals of the power switch, and a pull-down circuit coupled between the second terminal of the power switch and a gate terminal of the power switch. The pull-down circuit can be a pull-down transistor. The power switching circuitry can further include a feedforward resistor coupled between the first terminal of the power switch and a gate terminal of the pull-down transistor. The power switching circuitry can further include a voltage clamping circuit configured to limit a voltage at the gate terminal of the pull-down transistor and an additional transistor configured to selectively disable the voltage clamping circuit.

This invention provides a voltage converter and a circuit system using the same, the voltage converter having a switch, a latch, and a voltage clamping circuit. The switch receives an input signal and opens or closes according to the input signal. The latch receives a power supply voltage. The voltage clamping circuit has a first node, a second node, and a third node, the first node being electrically connected to an output terminal of the latch for outputting an output signal, the second node being electrically connected to another output terminal of the latch along with the switch, and the third node being a voltage follower node of the second node. Compared to the prior art, the voltage converter of this invention requires only a single power supply to operate, and the output signal is not unknown when the power supply is first turned on.

The application discloses a filter circuit and an implementation method and a filter device thereof, and relates to the technical field of filtering. The filter circuit comprises a signal filtering unit, an active filter unit, a clamping unit, a voltage input end and a voltage output end; wherein the output voltage flows into the signal filtering unit through the voltage input end, and the signal filtering unit is used for filtering the high-frequency small signal interference of the input voltage; the active filter unit is used for filtering the ripple and transient surge of the input voltage, and forming a direct current output voltage; the clamping unit is used for clamping the direct current output voltage at a fixed value and outputting through the voltage output end; wherein the signal filtering unit, the active filter unit and the clamping unit are electrically connected in sequence and arranged between the voltage input end and the voltage output end. According to the filter circuit of the embodiment of the application, the signal filtering unit can filter the high-frequency small signal interference; the active filter unit can filter the ripple and transient surge; and the clamping unit can clamp the direct current output voltage at a fixed value.

Embodiments of the present disclosure provide an adaptive ramp compensation circuit for a DC-DC converter based on an ACOT control mode, which includes a boost control circuit, a voltage clamping circuit, a pull-down control circuit, and an output circuit. The boost control circuit generates a boost control signal according to a first voltage signal and a clamping control signal, and provides the boost control signal to the output circuit via a first node. The voltage clamping circuit generates the clamping control signal and a voltage holding signal according to an output signal output by the output circuit, a clamping voltage signal, and a second voltage signal, provides the clamping control signal to the boost control circuit, and provides the voltage holding signal to the output circuit via the first node. The pull-down control circuit pulls down the output signal under control of a fixed on-time control signal of the DC-DC converter. The output circuit generates a ramp signal as the output signal under control of the boost control signal, holds a voltage of the output signal under control of the voltage holding signal, and outputs the output signal.

A circuit. In some embodiments, the circuit includes: a first pair of transistors, configured as a cross-coupled pair of transistors; a second pair of transistors, configured as another cross-coupled pair of transistors; and a first series combination of one or more voltage clamping transistors. A first transistor of the first pair of transistors may have a current-carrying terminal electrically coupled to a first end terminal of the first series combination of one or more voltage clamping transistors, and a first transistor of the second pair of transistors may have a first current-carrying terminal electrically coupled to a second end terminal of the first series combination of one or more voltage clamping transistors.

This application relates to the field of power electronics technology, and discloses an electronic device, a chip, and a negative voltage clamping circuit for the chip. The chip includes a power switch transistor adapted to control the chip to disconnect power supply to a load. The negative voltage clamping circuit includes: a negative voltage detection module configured to generate a negative voltage detection signal when the output pin voltage of the chip is detected to be less than a preset negative voltage threshold; and a clamping control module configured to generate a clamping control signal based on the negative voltage detection signal. The clamping control signal is used to control the power switch transistor to turn on, thereby clamping the output pin voltage of the chip with negative voltage. This application clamps the output pin voltage of the chip by utilizing the large current capability of the power switch transistor to quickly clamp the output pin voltage of the chip near a set threshold, shortening the time of negative voltage occurrence at the output pin to a sufficiently short duration, thereby greatly reducing the risk of latch-up.

The invention provides a reference current generation circuit and a nonvolatile memory. The reference current generation circuit is applied to the nonvolatile memory and comprises a correction current source, a voltage clamping circuit, a tracking current generation circuit and a current mirror circuit, the tracking current generation circuit and the current mirror circuit are electrically connected with the voltage clamping circuit, and the correction current source is electrically connected with the current mirror circuit; the voltage clamping circuit is used for accessing a reference voltage and clamping the reference voltage based on a negative feedback loop; the tracking current generation circuit is used for accessing a read operation voltage of a storage unit in the nonvolatile memory and generating a tracking current matched with the read operation transconductance of the storage unit based on the read operation voltage and a reference voltage; the current mirror circuit is used for generating and outputting the reference current corrected by the correction current source based on the tracking current. According to the invention, it is ensured that enough current margin is still available when the word line voltage changes, the reading operation accuracy and the reading speed are ensured, and the risk of reading voltage stress is avoided.

In a rectifier circuit, a bridge circuit rectifies an AC voltage. A voltage clamp circuit includes a clamp transistor, and a smoothing capacitor sequentially connected in series between an output terminal of the bridge circuit and a ground line, and controls on and off of the clamp transistor according to an output voltage of the bridge circuit. A DC / DC converter at a subsequent stage is connected in parallel with the smoothing capacitor.

A transient voltage suppressing (TVS) device including a first silicon-controlled rectifier and a voltage clamp having a first terminal and a second terminal. The first terminal is connected to a cathode of the first silicon-controlled rectifier.

The invention discloses an overvoltage protection circuit of a communication bus transmitter and a communication chip. The overvoltage protection circuit of the communication bus transmitter comprises a first output driving tube, a second output driving tube, a first diode, a second diode, a first control circuit unit and a second control circuit unit, the first control circuit unit comprises a first driving delay adjusting buffer unit, a second PMOS (P-channel Metal Oxide Semiconductor) tube, a second NMOS (N-channel Metal Oxide Semiconductor) tube and a gate-source voltage overvoltage protection unit; and the gate-source voltage overvoltage protection unit is used for clamping and stabilizing the gate-source voltage of the first output driving tube within a voltage threshold. When the circuit is used for a communication bus, overvoltage protection can be automatically realized, and a transmitter driving chip is not damaged by bus overvoltage; when the voltage of the communication bus is far higher than the voltage of the power supply of the transmitter driving chip, data can still be transmitted for normal communication; moreover, the circuit occupies a small chip area, saves the installation space required by an isolation element, and reduces the layout difficulty, size and cost of a system product.

The application discloses a self-powered driving circuit applied to a switching power supply circuit and relates to the technical field of integrated circuits, wherein the output end of a current driving switching circuit is connected with the second end of a Darlington power tube, the first input end and the second input end of the current driving switching circuit, the gate of a first field effect transistor and the gate of a second field effect transistor are all connected with a control chip; the first end of a voltage clamping circuit is connected with the second end of the Darlington power tube, and the second end is connected with the ground through an energy storage circuit; the gate of the first field effect transistor is connected with the control chip, the drain thereof is connected with the third end of the Darlington power tube, and the source thereof is connected with the ground; the drain of the second field effect transistor is connected with the fourth end of the Darlington power tube, and the source thereof is connected with the ground; the base and the collector of a first triode are both connected with the fourth end of the Darlington power tube, and the emitter thereof is connected with the ground through the energy storage circuit. The stability of the transformer output end voltage is improved.

The invention relates to a COB technology LED indicating lamp which comprises a constant current unit, a voltage clamping unit, a rectification unit, a surge protection unit and a light-emitting unit, the voltage clamping unit comprises four voltage-regulator tubes, the rectification unit comprises four switch tubes, the surge protection unit comprises at least one TVS tube, the negative electrode of each voltage-regulator tube in the voltage clamping unit is connected with the constant current unit, and the negative electrode of each switch tube in the voltage clamping unit is connected with the light-emitting unit. The positive electrodes are electrically connected with the positive electrodes of the switching tubes in the rectification unit in a one-to-one correspondence mode. One end of the constant current unit is connected with an AC power supply L phase line, and the other end is connected with the anode of one voltage-regulator tube and the cathode of one switch tube. One end of the resistor R2 is connected with the AC power supply N-phase line, and the other end is connected with the positive electrode of the other voltage-regulator tube and the negative electrode of the other switch tube. The positive electrode of the TVS tube of the surge protection unit is connected with the negative electrodes of the remaining two switch tubes and the positive electrode of the light-emitting unit, and the negative electrode is connected with the positive electrodes of the remaining two voltage-regulator tubes and the negative electrode of the light-emitting unit; according to the design, the voltage clamping unit is dispersed to each loop of the rectification unit, concentrated heating of a single voltage-regulator tube can be dispersed, and heat distribution of the whole lamp is more uniform.

The utility model provides an adjustable voltage clamping circuit. The adjustable voltage clamping circuit comprises a PMOSFET (P-channel Metal Oxide Semiconductor Field Effect Transistor) X1, voltage-regulator tubes D1, D2, D3 and D4, resistors R1, R2 and R3 and triodes Q1 and Q2, wherein the PMOSFET X1 is used for controlling output voltage, and the voltage-regulator tube D2 is connected to a G level and an S level of the X1 and is connected to the ground through the R2; the triode Q2 is connected to the G electrode and the S electrode of the X1, the base electrode of the triode Q2 is connected with the collector electrode of the triode Q1 through the resistor R1, and the voltage-regulator tube D1 is connected with the emitter electrode and the base electrode of the triode Q1; the base electrode of the triode Q1 is connected with the D electrode of the X1 through the resistor R3, the emitting electrode of the triode Q1 is connected with the voltage-regulator tube D4, the other end of the voltage-regulator tube D4 is connected between the R2 and the ground, and the voltage-regulator tube D3 is connected with the emitting electrode and the base electrode of the triode Q1; according to the utility model, through different circuit layout designs, the purpose of adjusting the clamping voltage is achieved, and the power consumption and the current are reduced, so that the A-type function requirements of an experiment are met.