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Power Supply Circuits
Current Limiting Circuits
Current Limiting Circuits
A simple solenoid driver uses incandescent lamp filaments as on-indicators to limit power consumption. High magnetic reluctance (opposition to flux) in the coil of an armature-driven device, such as a solenoid or relay, calls for a surge of activation current, followed hy a lower de level to remain on, since surge to on-current ratio is...
This circuit controls a solenoid by the operation of a single push-button switch. The circuit will supply loads of over 1 A and can be operated up to a maximum speed of once every 0.6 second. When power is first applied to the circuit, the solenoid will always start in its off position.
In many applications, a solenoid driver must first briefly supply a large amount of pull-in cnrrent, which quickly actuates the solenoid. Thereafter, the driver must supply a much lower holding cnrrent to avoid burning the solenoid out. To avoid using the customary, cumbersome, large capacitors or power-wasting resistors, you can use the...
One-Zener Precise Limiter
A limiter circuit that requires matched zener diodes can instead use one zener with a full-wave diode bridge. The
Inrush Current Limiter Circuit
Q1 is an npn Darlington and Q2 is a prip Darlington. MOV1 is a metal-oxide varistor and R8 is an thermistor for limiting inrush current. This circuit limits ac line current to a load. When a predetermined interval has passed, RY1 shorts out thermistor or resistance RB. R4 can be 150 kQ if R9 is not used. If power is removed,
Inrush Current Limiter Circuit
A 7805 can be configured as a constant-current regulator, to serve as an inrush current limiter. Rl will have 5 V across it at all times so the total current through 11 will be 5 V/R1 + 5 mA, the 5 mA being the regulator operating current.
SN75064 ~ SN75067 current Darlington circuit diagram of a switch
SN75064 ~ SN75067 is a monolithic, high-voltage, high-current Darlington switch output termination
MIC5156- composed triggered rising high current switching circuit
As shown using MIC5156- is a composition having a current limiting function, and a lot of high output current is turned off may be low with or without regulator switching regulator circuit. S terminal vacant, and the gate - plus a l6 V Zener
MC1411 series Darlington current internal structure of a drive circuit
MC1411 series of Darlington Drive current internal structure Darlington current driver has a small, consistent, and high reliability parameters, especially for high-voltage,
CW117 CW217 CW317 charger has a current-limiting protection configuration
As shown in Figure is a limiting protection charger. VT transistors and resistors R3 form limiting network. Seen from the figure, the resistor R3 is the base of transistor VT e
Current Limiting Power Supply
This is a 1-amp variable-voltage PSU. It adjusts from about 3v to 24v: and has the added feature that you can limit the maximum output current. This is invaluable when (for example) you power-up a project for the first time or soak-test a piece of equipment.
13 Volt 20 Amp with current limiter
This PSU has been especially designed for current-hungry ham radio transceivers. It delivers safely around 20Amps at 13.8V. For lower currents, a separate current limiting output, capable of 15ma up to a total of 20A has been added.
Circuit adds latch-off current limit to regulator
The circuit is based on IC1, an LTC1430 PWM controller. The current-limiting feature of the IC operates by sensing the voltage across the high-side MOSFET and compares it with a threshold voltage developed across R3.
Circuit provides hiccup-current limiting
The three major types of current-limit-protection mechanisms are constant, foldback, and hiccup. Hiccup current limit performs the best of the three types; however, the implementation is rather complex. In this scheme, upon detection of an overcurrent event, the whole power supply shuts down for an interval before it tries to power itself up...
dc/dc converter`s current-limit
The circuit in Figure 1 shows how a thermistor applies temperature compensation to the circuit`s output-current limit. The MAX1714`s linear current-limit (ILIM) input range at Pin 6 of IC1 spans 0.5 to 2V, which corresponds to current-limit thresholds of 50 to 200 mV, respectively.
Current-Limited DC/DC Converter
Figure 1 shows a 5V to 12V boost converter ideal for USB applications. The converter has a selectable 100mA/ 500mA input current limit, allowing the device to be easily switched between the USB low and high power modes. Efficiency, shown in Figure 2, exceeds 85%.
Current-Limit Switch Is Digitally Programmable
Current-limit switches are virtually ubiquitous in system controls. They provide a safe means for regulating the current delivered to a load circuit. The switches allow the load current to increase to a programmed limit but no higher. This application note illustrates the implementation of a digitally programmable current-limit switch using...
Current Regulators For LEDs
The following are current regulator circuits that can be used to drive light emitting diodes. As always, take time to do some testing before attempting to use these circuits in actual applications.
Regulator Combination Circuits
There are a number of ways to obtain the low voltages required to run small projects from the wall power outlet. The simplest way is to buy a factory-built molded supply which is designed to plug directly into the wall outlet. Some such supplies have an internal voltage regulator and need no additional parts, others provide an unregulated DC...
Volt regulators such as the LM708, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be used (See the project on the 3-part variable power supply). The power transistor is used...
Auto poweroff for power supplies circuit
Probably the easiest way of doing automatic switch off is with relay logic. In the diagram, the box marked RL1 is the coil, the 2 in the coil box tells you there are two sets of contacts somewhere on the circuit, operated by this coil. In this simple circuit, it's easy to see them!Sw1 is a momentary push switch. When it's pushed (contacts...
Current Limit Circuit for Voltage Regulator
This is a low cost circuit that adds precise current limit functionality to a voltage regulator.
Test wall socket with current limiting
Anyone who frequently builds, repairs and tests equipment powered by mains voltage, will certainly have met with an unpleasant surprise when the plug inserted into the socket (or later) - loud explosion, destruction of equipment, flying pieces of components, circuit breakers tripped, darkness in the whole house and smoked plug :). Th
555 IC PWM Motor Control with Current Limiter
To provide rapid motor speed changes and motor direction reversal, four outputs drive a MOSFET H-bridge. N-channel devices are the lower rail power MOSFETs and P-channels are the upper MOSFETs. All of them are driven by the TC4469. A small series resistor helps prevent gate oscillation and slows transition time in the lower rail devices, helping t
Issues with the OPA548 current limiting
In order to eliminate noise, I`ve used a 100uF capacitor and a 100nF bypass capacitor across the supply and two 10nF capacitors in parallel with the resistors Rda and Rdb (those are 10K each), As for the current limiting, I`ve used a 22K resistor paralleled with a 10nF capacitor, from pin 3 (Ilim) to V-. I`ve tied pin 7 (E/S) to V+. I`ve used two
Voltage-controlled Current-limited switcher circuit
My product requires a voltage-controlled, current-limited power supply and for a number of years I have used various switcher chips with an op-amp to feed back a current sense voltage to the feedback pin. For the last couple of years I have been using an LM22680, but I seem to get variable results board to board. (Output voltage not consistent) I
Simple LM317 variable voltage supply does it limit current too
Assuming I can get 5V in example after adjusting the pot in real use, will the 240 ohm resistor limit the current, or do I have to add something else on top of that afterwards If it does (I can have var. voltage + current limit) I assume I will need to up the resistor power specifications as the current will flow through them (or my...
power supply Transistor current limiter microcontroller controlled
Rsense would cause Q2 to conduct if at a threshold (0. 65V assumably) and Rbias will determine how much it will be limited, however that is unclear to me, especially if Rsense will be somewhere highside and just turning on Q2 with my uC seems to not do anything (in simulation at least) How would I come up with the formulas for a variable limit...
Charging capacitor bank with current limiting circuit
A useful current limiting circuit (shown below), that allows me to select a maximum current through a load. The circuit is set to give a 480 mA max current. As the load resistance increases, the SER of the limiting circuit drops away. The following plot shows current through the load versus load resistance. . . However, what happens if I want to...
op amp Why does this current limiter circuit oscillate
Make a 0-25 mA current limiter. I want to take a control voltage of 0-5 V as input and have it control a current of 0-25 mA through a restive load (the restive load may vary between 0-200, it`s represented as R2 below). The O2 op-amp is used to make a differential amplifier with a gain of 2. Example: 25mA of current through the lo
voltage transistor loop to limit the current
The other transistor (T2) is controlled by the current flowing through the resistor (R1). If a DALI slave unit is connected, this current will be the same as that flowing through the power transistor. The value of the resistor is chosen in such a way that when the current exceeds 250 mA the voltage level across the resistor will open the transisto
Transistor current limit circuit power handling
Designing a simple current limiter, which charges a large (4. 7mF) capacitor with a charge current of (roughly) 500mA from a supply voltage from about 10-20V - see the below circuit. My dilemma is that I already have a bunch of MMBT2222A and it would be nice to use this part without another line item. Whilst it can happily push 500mA through t
Free Energy Circuits
Battery Charger Circuits
AC-DC & DC-DC Circuits
Solar Cell Circuits
Micro Power Circuits
High Voltage Circuits
Switching Power Supply Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity