AC-DC & DC-DC Circuits
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ICs requiring 3 or 6 volts can be run from a battery or fixed regulated supply of a higher voltage by using the circuit shown. The transistor should be mounted on a heatsink as considerable power will be dissipated by its collector. Additional filtering can.... -
The circuit behaves like a zener diode over a large range of voltages. The current passing through the voltage divider R1-R2 is substantially larger than the transistor base current and is in the region of 8 mA. The stabilizing voltage is adjustable over the.... -
This circuit enables transistorized items such as radio, cassettes, and other electrical devices to be operated from a car"s electrical supply. The table gives values for resistors and specified diode types fordifferent voltage. Should more than one voltage.... -
This circuit gives a regulated output of between 5 V and 15 Vdc, adjusted and set by a preset resistor. Current output up to about 350 mA.. -
This circuit utilizes the quasi-complementary output stage of the popular LM380 audio power IC. The device is internally biased so that with no input the output is held midway between the supply rails Rl, which should be initially set to mid-travel, is used.... -
For positive protection of electrical or electronic equipment, use this against excessive supply voltage. Due to improper switching, wiring, short circuits, or failure of regulators, an electronic crowbar circuit can quickly place a short circuit across the.... -
To safeguard portable, emergency power repeaters from reverse or excessive voltage, Dl prevents incorrect polarity damage, and zener voltage determines the maximum voltage that will reach the rest of the circuitry.. -
These circuits provide overvoltage protection in case of voltage regulator failure or application of an external voltage. Intended to be used with a supply offering some form of short circuit protection, either foldback, current limiting, or a simple fuse..... -
Zener diode ZD1 senses the supply, and should the supply rise above 6 V, Ql will turn on. In turn, Q2 conducts clamping the rail. Subsequent events depend on the source supply. It will either shut down, go into current limit or blow its supply fuse. None of.... -
When using a regulated power supply to reduce a supply voltage, there is always the danger that component failure in the power supply might lead to a severe overvoltage condition across the load. To cope with overvoltage situations, the circuit is designed.... -
The circuit will produce the current relationship to within 2% using 1% values for Rl through R5. This includes variations in Rl from 100 ohm to 2000 ohm. The use of large resistors for Rl through R4 minimizes the error due to Rl variations.. -
In this circuit, a TU31 shunt regulator is used to sense the output voltage. The TU31 drives the LED of a 4N28 optocoupler which provides feedback to the MAX641 while maintaining isolation between the input, +12 V, andJhe output, +15 V. .. -
Positive output step-up and step-down de-de converters have a common limitation in that neither can handle input voltages that are both greater than or less than the output. For example, when converting a 12-V sealed lead/acid battery to a regulated +12 V.... -
This linear post regulator provides 12 V at 3 A. It employs TL431 reference Ul which, without additional amplification, drives TMOS MTP3055A gate Ql series pass regulator. Bias voltage is applied through Rl to Q1"s gate, which is protected against.... -
The diagram is a power supply circuit using the isolated feedback capabilities of the TL3103 for both current and voltage sensing. This supply is powered fromthe ac power line and has an output of 5 Vat 1.5 A. Both output voltage and current are sensed and.... -
This de adapter provides a regulated 9-V source for operating a Kenwood TR-2500 hand-held transceiver in the car. The LM317T"s mounting tab is electrically connected to its output pin, so take this into account as you construct your version of the adapter. .. -
A MAX634 inverting regulator is combined with a MAX630 to provide a dual tracking ±15 output from a 12-V battery. The reference for the -15 V output is derived from the positive output via R3 and R4. .. -
The supply receives + 20 Vdc from the rectifier/filter section. This is applied to pins 11 and 12 of the uA723, as well as to the collector of the 2N3055 series-pass transistor. The output voltage is sampled through R1 and R2, providing about 7 V with.... -
The supply receives -20 V from the rectifier/filter which is fed to the collector of the Darlington pnp pass transistor, a TIP105. The base drive to the TIP105 is supplied through resistor R5. The base of the TIP105 is driven from Vz terminal at pin 9,.... -
This power supply delivers plus and minus 9 V to replace two 9-V batteries. The rectifier circuit is actually two separate full-wave rectifiers fed from the secondary of the transformer. One full-wave rectifier is composed of diodes D1 and D2, which.... -
The supply 6-66 can be used for supply output voltages from 1 to 35 V. The line transformer should be selected to give about1.4 times the desired output voltage from the positive side of filter capacitor C1 to ground. Potentiometer R2 sets the output.... -
This circuit generates three supply voltages using a minimum of components. Diodes D2 and D3 perform full-wave rectification, alternately charging capacitor C2 on both halves of the ac cycle. On the other hand, diode D1 with capacitor C1, and diode D4 with.... -
Many systems require one or more relatively low-current voltage sources which can be programmed tna few predetermined levels. The circuit shown above produces positive output levels, but could be modified for negative or bipolar outputs. Q1 is the series.... -
It is usually desirable to have the remote transmitter of a 4 to 20 mA current loop system powered directly from the transmission line. In some cases, this is not possible because of the high-power requirements set by the remote sensor/transmitter.... -
This circuit consists of an astable multivibrator driving a push-pull pair of transistors into the transformer primary. The multivibrator frequency should~equal around 1 or 2kHz. .. -
The IC8211 provides the voltage reference and regulator amplifier, while Ql is the series pass transistor. Rl defines the output current of the IC8211, while Cl and C2 provide loop stability and also act to suppress feedthrough of input transients to the.... -
A TMOS power FET, Ql, and an LM393 comparator provide a high-efficiency rectifier circuit. When V,. exceeds V,, Ul"s output becomes high and Ql conducts. Conversely, when VB exceeds V,., the comparator output becomes low and Ql does not conduct. The.... -
In the circuit shown, a CMOS op amp controls the current through a p-channel HEXFET power transistor to maintain a constant voltage across RL The current is given by: 1 ~ VREF/Rl. .. -
One v;ay to provide good negative-voltage regulation is with a low-dropout positive-voltage regulator operating from a well-isolated secondary winding of switch-mode circuit transformer. The technique works with any positive-voltage regulator, although.... -
In this circuit. a negative output voltage de-de converter generates a -5 V output at pin A. In order to generate -5 Vat point A, the primary of the transformer must fly back to a diode drop more negative than -5 V. If the transformer has a tightly coupled.... -
In the circuit, Ql and Q2 are connected in the classic SCR or thyristor configuration. Where higher input voltages or minimum component count are required, the circuit for thyristor boost can be used. The thyristor is running in a linear mode with its.... -
This circuit provides a continuous supply of regulated + 5 V, with automatic switch-over between line power and battery backup. When the line-powered input voltage is a + 5 V, it provides 4A V to the MAX630 and trickle charges the battery, If the....
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
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.... -
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.... -
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.... -
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.... -
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,.... -
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.... -
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.... -
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.....
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