LA4440 Amplifier Circuit

LA4440 is a dual channel audio amplifier IC. It can be used in two modes; one is Stereo amplifier and another Bridge amplifier mode. The LA4440 is a monolithic linear IC from Sanyo. Here I give the both circuit mode of amplifier using IC LA4440.

Features of IC LA4440

• It has 46dB of ripple rejection
• Low distortion
• Good channel separation
• Thermal protector
• Overvoltage protector
• Surge voltage protector

LA4440 Stereo Amplifier Circuit

When the IC LA4440 is Stereo mode in the circuit, its output power is 6w+6w. In stereo mode use two pieces speaker of 2Ωto8Ω.
In the stereo amplifier configuration given below, C11 and C12 are output capacitor. But i ignore them from the circuit of bridge amplifier.

Fig-1: LA4440 Stereo Amplifier Circuit Diagram

LA4440 Bridge Amplifier Circuit

When the IC LA4440 is in Bridge mode in the circuit, its output power is 19w. In bridge mode use 4Ω-8Ω speaker. If you want stereo output(19w+19w) in bridge mode then use two copies of amplifier circuit of given below. Resistor R3&R4 is to adjust the voltage gain and for making input signal of inverting amplifier.

Fig-2: LA4440 Bridge Amplifier Circuit Diagram

Circuit description for both, stereo and bridge amplifier mode

C10 is filter capacitor used to reduce the ripple of supply voltage. Don’t decrease the value of capacitor C6&C7 less than 100uF, 10v, it may causes of the output at low frequencies goes lower. The pin-6 of LA4440 amplifier circuit  is audio input pin; it used in stereo amplifier mode but in bridge mode it is grounded. C8&C9 are polyester film capacitor used to preventing oscillation, and R1&R2 used for the same reason as filter resistor. Though the maximum supply voltage for both circuit of amplifier is 18V but we recommend to use a 12V,3A power supply. Use a good quality heat sink with LA4440.

I think here you see little comparison between stereo and bridge amplifier of LA4440. If you want to make this amplifier project, then I recommend you the bridge one. I think it is ideal for a beginner. And I love its wattage rather than Stereo mode. There is also a possibilities as I say, make two copies of circuit of bridge amplifier for stereo, it will give you 19w+19w of audio power output.

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New Automatic Shutoff Battery Charger Circuit Diagram

This is a New Automatic Shutoff Battery Charger Circuit Diagram. This automatic shutoff battery charger circuit diagram Adjust by setting the 500 ohm resistor while attached to a fully charged battery.

New Automatic Shutoff Battery Charger Circuit Diagram

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Switching inverter for 12v systems circuit diagram

This PWM control circuit provides the control pulse to the DMOS Power Switch in the flyback circuit. The output of the PWM is a pulse whose width is proportional to the input control voltage and whose repetition rate is determined by an external clock signal. 

To provide the control input to the PWM and to prevent the output voltage from soaring or sagging as the load changes the error amplifier and reference voltage complete the design. They act as the feedback loop in this control circuit much like that of a servo control system.

Switching inverter for 12v systems circuit diagram

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Speach Amplifier Circuit Diagram

This circuit is intended to be placed in the same box containing the loudspeaker, forming a compact microphone amplifier primarily intended for speech reinforcement. A device of this kind is particularly suited to teachers, lecturers, tourists guides, hostesses and anyone speaking in crowded, noisy environment.

The circuits heart is formed by the TDA7052 Audio power amplifier IC, delivering a maximum output of 1.2W @ 6V supply. An external microphone must be plugged into J1, its signal being amplified by Q1 and fed to IC1. R1 acts as a volume control and C3 tailors the upper audio frequency band, mainly to reduce the microphone possibility of picking-up the loudspeaker output, causing a very undesirable and loud "howl", i.e. the well known Larsen effect. Therefore, C3 value can be varied in the 4n7 - 22nF range to ensure the best compromise from speech tone quality and minimum Larsen effect occurrence. Dynamic or electrets microphone is warmly recommended. It has a useful feature that can be used to momentarily mute the microphone by connecting SW1 shown in diagram.

Circuit Diagram:

 Speach Amplifier Circuit Diagram

Parts	Description
R1	22K
R2	1M
R3	15K
R4	470R
R5	47K
R6	4.7K
C1	100nF-63V
C2	100nF-63V
C3	100nF-63V
C4	10nF-63V
C5	220uF-25V
C6	10uF-25V
Q1	BC547
IC1	TDA7052 B1
J1	Mono Jack Socket
B1	6V Battery
SW1	SPST Slider Switch
SW2	SPST Toggle Switch

Notes:

• Please note that hands-free, uni-directional headset or ear clip microphone types are very well suited for this device, as also are Clip-on Lavaliere or Lapel microphones.
• If a small electrets capsule is used for the microphone, R5, R6 and C6 must be added to the circuit to provide power supply.
• Choose a loudspeaker as large as possible, in order to increase circuit performance.
• You can use also two 4 Ohm loudspeakers wired in series or two 8 Ohm types wired in parallel in order to obtain better results.
• The box containing the amplifier and loudspeaker(s) can be fitted out with a belt and carried like a shoulder-bag or, if you build a smaller unit, it can be used as a Pick & Go Belt Clip Speaker.

Source : www.redcircuits.com

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LED Volt Meter Circuit

Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when fully charged. The LED voltmeter uses four Zener diodes to light the LEDs at the precise breakdown voltage of the Zener diodes. Usually the Zener diode requires 1.6 volts in excess than its prescribed value to reach the breakdown threshold level. When the battery holds 13.6 volts or more, all the Zener breakdown and all LEDs light up. When the battery is discharged below 10.6 volts, all the LEDs remain dark. So depending on the terminal voltage of the battery, LEDs light up one by one or turns off.

Circuit diagram:

 LED Volt Meter Circuit Diagram

Author: D. Mohan Kumar Copyright: electroschematics.com

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Model Railway Short Circuit Beeper

Short circuits in the tracks, points or wiring are almost inevitable when building or operating a model railway. Although transformers for model systems must be protected against short circuits by built-in bimetallic switches, the response time of such switches is so long that is not possible to immediately localise a short that occurs while the trains are running, for example. Furthermore, bimetallic protection switches do not always work properly when the voltage applied to the track circuit is relatively low. The rapid-acting acoustic short-circuit detector described here eliminates these problems. However, it requires its own power source, which is implemented here in the form of a GoldCap storage capacitor with a capacity of 0.1 to 1 F. A commonly available reed switch (filled with an inert gas) is used for the current sensor, but in this case it is actuated by a solenoid instead of a permanent magnet.

An adequate coil is provided by several turns of 0.8–1 mm enamelled copper wire wound around a drill bit or yarn spool and then slipped over the glass tube of the reed switch. This technique generates only a negligible voltage drop. The actuation sensitivity of the switch (expressed in ampère-turns or A-t)) determines the number of turns required for the coil. For instance, if you select a type rated at 20–40 A-t and assume a maximum allowable operating current of 6 A, seven turns (40 ÷ 6 = 6.67) will be sufficient. As a rule, the optimum number of windings must be determined empirically, due to a lack of specification data. As you can see from the circuit diagram, the short-circuit detector is equally suitable for AC and DC railways. With Märklin transformers (HO and I), the track and lighting circuits can be sensed together, since both circuits are powered from a single secondary winding.

Coil L1 is located in the common ground lead (‘O’ terminal), so the piezoelectric buzzer will sound if a short circuit is present in either of the two circuits. The (positive) trigger voltage is taken from the lighting circuit (L) via D1 and series resistor R1. Even though the current flowing through winding L1 is an AC or pulsating DC current, which causes the contact reeds to vibrate in synchronisation with the mains frequency, the buzzer will be activated because a brief positive pulse is all that is required to trigger thyristor Th1. The thyristor takes its anode voltage from the GoldCap storage capacitor (C2), which is charged via C2 and R2.

The alarm can be manually switched off using switch S1, since although the thyristor will return to the blocking state after C2 has been discharged if a short circuit is present the lighting circuit, this will not happen if there is a short circuit in the track circuit. C1 eliminates any noise pulses that may be generated. As a continuous tone does not attract as much attention as an intermittent beep, an intermittent piezoelectric generator is preferable. As almost no current flows during the intervals between beeps and the hold current through the thyristor must be kept above 3 mA, a resistor with a value of 1.5–1.8 kΩ is connected in parallel with the buzzer. This may also be necessary with certain types of continuous-tone buzzers if the operating current is less than 3 mA. The Zener diode must limit the operating voltage to 5.1 V, since the rated voltage of the GoldCap capacitor is 5.5V.

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24V to 12V 400W DC Inverter Circuit

24V to 12V 400W DC Inverter Circuit Diagram

24V to 12V 20A 400W DC to DC Inverter. Does little to change my PV system 12v 24v me the problem arose of what to do with investors who already had 12V. I was looking for a pattern online and found several schemes with linear regulators 20A, this solution although quite simple, due to the huge losses they have is not advisable. Ideally, a converter switched, high-performance. At the end I found nothing I liked and decided to design my own. Circuit characteristics: Output current: 20A at 12V (15A continuous and 30A Momentary), Input voltage: 18 to 30V DC, Output voltage: 5 to 20V, Operating Frequency: 70kHz, Effectiveness: 95%, 400W maximum power, Protections: Above current (30A) in the F1 circuit, D1 and F1 polarity in the circuit.

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Flashing Lamp circuit

This is flashing lamp circuit.This circuit operate with 6V power supply.You can fix this circuit for your bick or for your car.Here I have used common transsistor 2N3904.
Note
# Build this on a PCB
# This circuit operates with 6V

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Automobile turn signal circuit

This is a circuit which can use as a sequential signal light in automobiles.so the vehicle owners can use this to modify their vehicles.

Notes.
# This circuit need 12v power so you can provide it from your vehicle.

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230V LED Indicator circuit

This is very useful circuit for you.You can use this circuit as a current indicator.The special thing of this circuit is this circuit operates 110V to 230V.I myself have use this circuit for my door bell.so visitors who come home at night can easily see the door bell.you your self think different way and do something newly
Parts

R2 = 1M-1/2W
R1 = 470R-1/2W
D1 = 1N4007
D2 = 1N4007
D3 = 1N4007
D4 = 1N4007
D5 = 5mm. Blue LED
C1 = 220nF-275vAC

Note

# When you deal with 230V be careful.If you are too little Dont try this circuit
#Use Quality parts.Specially think about the W of your parts

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Mobile Cellphone Battery Charger Circuit

Charging of the mobile phone, cellphone battery is a big problem while traveling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless.A fully charged battery becomes necessary especially when your distance from the nearest relay station increases. Here’s a simple charger that replenishes the cellphone battery within two to three hours. Basically, the charger is a current-limited voltage source. Generally, cellphone battery packs require 3.6-6V DC and 180-200mA current for charging.These usually contain three NiCd cells, each having 1.2V rating. Current of 100mA is sufficient for charging the cellphone battery at a slow rate. A 12V battery containing eight pen cells gives sufficient current (1.8A) to charge the battery connected across the output terminals. The circuit also monitors the voltage level of the battery. It automatically cuts off the charging process when its output terminal voltage increases above the predetermined voltage level.






Parts:

P1 = 20K
P2 = 20K
R1 = 390R
R2 = 680R
R3 = 39R-1W
R4 = 27K
R5 = 47K
R6 = 3.3K
R7 = 100R-1W
C1 = 4.7uF-25V
C2 = 0.01uF
C3 = 0.001uF
D1 = 5.6V-1W Zener
D2 = 3mm. Red LED
Q1 = SL100

S1 = On/Off Switch
B1 = 1.5vx8 AA Cells in Series
IC1 = NE555 Timer IC


Timer IC NE555 is used to charge and monitor the voltage level in the battery. Control voltage pin 5 of IC1 is provided with a reference voltage of 5.6V by zener diode D1. Threshold pin 6 is supplied with a voltage set by P1 and trigger pin 2 is supplied with a voltage set by P2. When the discharged cellphone battery is connected to the circuit, the voltage given to trigger pin 2 of IC1 is below 1/3Vcc and hence the flip-flop in the IC is switched on to take output pin 3 high. When the battery is fully charged, the output terminal voltage increases the voltage at pin 2 of IC1 above the trigger point threshold.
This switches off the flip-flop and the output goes low to terminate the charging process. Threshold pin 6 of IC1 is referenced at 2/3Vcc set by P1. Transistor Q1 is used to enhance the charging current. Value of R3 is critical in providing the required current for charging. With the given value of 39-ohm the charging current is around 180 mA. The circuit can be constructed on a small general-purpose PCB.
For calibration of cut-off voltage level, use a variable DC power source. Connect the output terminals of the circuit to the variable power supply set at 7V. Adjust P1 in the middle position and slowly adjust P2 until LED (D2) goes off, indicating low output. LED should turn on when the voltage of the variable power supply reduces below 5V. Enclose the circuit in a small plastic case and use suitable connector for connecting to the cellphone battery.

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Build 10 Watt Audio Power Amplifier Circuit

10W Audio Power Amplifier Circuit

10W PA.The 10 watts power amplifier circuit with the aid of transistor describe right here is an audio amplifier with output power of 10W.Used as a low frequency type AB Amplifier. Transistor has high output present and very low distortion.This 10W audio amplifier circuit diagram using Transistor is good for small room or car audio device.This circuit is a general-purpose 10W audio amplifier for moderate-power PA or modulator use in an AM transmitter.

With better voltages and a change in bias resistors,up to 30 W may additionally be obtained.

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60W POWER AMPLIFIER CLASS B CIRCUIT DIAGRAM

60W POWER AMPLIFIER CLASS B CIRCUIT DIAGRAM

Capacitor C1 regulates the low frequencies (bass), as the capacitance grows, the low frequencies are getting louder. Capacitor C2 regulates the higher frequencies (treble), as the capacitance grows, the higher frequencies are getting quieter.

This is a class B amplifier, this means, that a current must flow through the end transistors, even if there is no signal on the input. This current can be regulated with the 500 Ohm trimmer resistor. As this current increases, the sound of the amplifier is better, but output transistors are dispatching more heat. If the current is decreased, the transistors are dispatching less heat, but the sound quality is decreased.

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Electromagnetic Sensor Circuit Using 741 IC

This is a design schematic to sensor the electromagnetic field. This circuit is based or built by 741 IC. This IC is an op-amp. The circuit can detect the field even hidden wrings. This is the figure of the schematic.


A 1mH inductor is used for sensing the electric field. The electric field will induce a small voltage in the sensor inductor and this induced voltage is amplified by the op amp. The headphone connect at the output of the op amp will give an audio indication of the electric field. For example, the electric field around a main transformer can be heard as a 50 Hz hum. The POT R4 can be used to adjust the gain of the amplifier. By keeping the sensor inductor near to a telephone line, you can even hear the telephone conversations. All electrolytic capacitors must be rated at least 15V. The switch S1 can be a slide type ON/OFF switch. The POT R4 can be used to adjust the gain. It is better to have a radial type inductor for L1.

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Usb Power Socket Circuit Diagram

Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100 mA of continuous current at 5V to the peripherals that are connected to the bus. So a USB port can be used, without any trouble, for powering 5V DC operated tiny electronic gadgets. Nowadays, many handheld devices (for instance, portable reading lamps) utilise this facility of the USB port to recharge their built-in battery pack with the help of an internal circuitry.Usually 5V DC, 100mA current is required to satisfy the input power demand. Fig. 1 shows the circuit of a versatile USB power socket that safely converts the 12V battery voltage into stable 5V.

Circuit diagram:

Fig. 1: Circuit of USB power socket

This circuit makes it possible to power/recharge any USB power-operated device, using in-dash board cigar lighter socket of your car. The DC supply available from the cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1). Capacitor C1 buffers any disorder in the input supply.Resistors R1 and R2 regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket.

Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage. Assemble the circuit on a general-purpose PCB and enclose in a slim plastic cabinet along with the indicator and USB socket. While wiring the USB outlet, ensure correct polarity of the supply. For interconnection between the cigar plug pin and the device, use a long coil cord as shown in Fig. 2. Pin configuration of LM317L is shown in Fig. 3.

Author : T.K. Hareendran - Source : EFY Mag

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Dual Input Far Field Noise Suppression Microphone Amplifier Circuit

This is a circuit diagram for microphone amplifier. This circuit is using LMV1090 as based op amp signal in the circuit. This is the figure of the circuit;

The LMV1090 is a fully analog dual differential input, differential output, microphone array amplifier designed to reduce background acoustic noise, while delivering superb speech clarity in voice communication applications. The LMV1090 preserves near-field voice signals within 4cm of the microphones while rejecting far-field acoustic noise greater than 50cm from the microphones. Up to 20dB of far-field rejection is possible in a properly configured and using ±0.5dB matched microphones. [Schematic circuit source: National Semiconductor Notes].

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Reducing Treble tone circuit

Treble reducer circuit above is an example of a simple circuit and is suitable to be used as experimental material and analysis of the workings of the circuit. 

As I mentioned earlier the bass reducer series, this series actually has the same working principles with a series of bass reducer. Where these circuits utilize capacitors nature of the charge and discharge. The difference of the damping function obtained from the difference of the capacitor. If the series bass reducer series capacitors are mounted on the op-amp input lines, while in this treble reducer series capacitors are mounted parallel with the strengthening of the op-amp prisoners. Installation of this circuit has a parallel in the work analysis in contrast with the installation of the series on a series of bass reducer. The difference is that the installation of the series, so we URLs that are easy to understand how a wire working capacitors for high frequency signal, so with high frekuesni so automatic signal to be passed to the output terminal by a capacitor. But if we put a parallel between the output capacitor with the terminals, then automatically because the capacitor is considered as a wire so the voltage on the capacitor is near 0 volts, so the output voltage will also follow the voltage on the capacitor because they connect parallel. As with the low frequency signal, the capacitor is considered open and makes voltage wire that fell to him is to approach the input voltage. To understand how the capacitor can be regarded as a wire or an open switch I mentioned in my post about the working principles of capacitors and a series of bass reducer.

Indeed, when examined in detail, not only the capacitors that play a role here but the component resistors and op-amp also affect. But I can confirm that the main function is performed by a capacitor reduction. Series resistors are intended to be installed that will flow into the capacitor can be adjusted so that it influences the charge and discharge the capacitor will make the appropriate damping.

Take a look at the picture above the treble reducer circuit and also the image output signal. There are two function generator as input and has a signal with different frequencies. The first signal of amplitude 1 volt and low frequencies, the two signals with an amplitude of 1 volt and with high frequency. At the time of our input select switch position to the relationship with the input low frequency signal, the signal output will be nearly equal to the input signal such as no change. Whereas if we switch position to link high-frequency input signal then the output signal amplitude will be damped near 0 volts.

Example treble reducer circuit is very simple and can you develop more in accordance with the desires and your needs. At least with understanding the working principle of this circuit we can apply a time when we are required to perform the function of damping trebele.

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Make this Temperature Indicator Circuit with Sequential LED Display

In some of my earlier articles we have seen a few simple and interesting temperature indicator circuits. All these circuits are useful in some or the other ways, however these are not equipped with  step wise temperature level indicator arrangement and therefore tracking the varying levels of temperature cannot be identified using them.

The present design eliminates the above issue, as here the entire temperature range becomes visible through an arrangement of an LED array.
The LEDs in this circuit reads the temperature levels discretely via 20 steps of LED indications.
The proposed sequential LED temperature indicator circuit is definitely the simplest to build, since it is based on a single outstanding IC LM3914 from TEXAS INSTRUMENTS, which single handedly performs the whole action of displaying the readings in a sequential manner.
The LEDs show an incrementing temperature through a single illuminated LED at the relevant positions of the array, thus the present design shows a dot mode indication instead of a bar graph. The dot mode arrangement specifically helps to save battery power because only one LED is involved for the required indication at any instant.  

The IC LM3914 is basically a millivolt measuring device which is able to convert a varying milli volt input into a corresponding LED readout at its output pin outs.

Here the input is derived from another interesting IC LM35 from TEXAS INSTRUMENTS, which is configured as an ambient temperature sensor device.

The IC LM35 coverts the temperature differences around it, directly into varying milli volts across its output.
For every single degree change in the temperature, the IC LM35 generates an output with a 10 mV variation.
This correspondingly varying milli volts is applied at the input of the IC LM3914, which readily accepts these variations, making them visible at the output through the connected LEDs.
Thus as the temperature around the IC LM35 increases, it generates a correspondingly increasing mV  across its outputs which is in turn transformed by the IC LM3914 into an LED readout, displaying the relevant level of the sensed temperature.
The LED array should be appropriately calibrated, through some trial and error and some practical experimentation.

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Audio Graphic Equalizer Circuit Using Op Amp

This is a design circuit for audio graphic equalizers, that are very common as commercial products but circuits for them are very rarely published. This circuit is a simple design circuit. The circuit is need an op-amp for amplifying the input signal. This is the figure of the circuit.


Only one gyrator stage is shown: all 7 gyrators are the same circuit, only the capacitors change, as shown in the chart. I have shown three of the seven faders to show where they go. A gyrator is a circuit using active devices and transistors to simulate an inductor. In this case the gyrator is the transistor acting with R1, R3 and C2. It could just as easily be a unity gain op-amp. The circuit includes three formulae: one which gives f, the the centre frequency of the band. The second shows how the Q is related to the capacitor ratio. The third shows the impedance presented by the circuit. Note that this includes 3 terms, the first purely resistive, the second is the capacitive contribution from C1 and the third is an inductive term from the gyrator.

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Frequency to Voltage Converter Circuit

IC LM2917 Frequency to Voltage Converter

IC LM2917 IC chip is designed specifically as a Frequency to Voltage Converter or Frequency to Voltage converter. In its use to applications Frequency to Voltage Converter IC LM2917 requires few external components. 

There are several examples of applications of Frequency to Voltage Converter IC LM2917 datasheet that is included in the LM2917 IC. In this article series Frequency to Voltage Converter IC also taken from the LM2917 datasheet. The advantages of single chip LM2917 Frequency to Voltage Converter is able to provide instantaneous volt output o at time of frequency change 0 Hz. Very easy to apply in measuring the output frequency with the formulation of single-chip Frequency to Voltage Converter VOUT = FIN x VCC x R1 x C1.

Then the single-chip LM2917 Frequency to Voltage Converter This configuration requires only the RC only in frequency doubling. And has an internal zener regulator to aimlessly accuracy and stability in frequency-to-voltage conversion process.

Application circuit Figure IC LM2917 as Frequency to Voltage Converter

Feature-owned single-chip LM2917 Frequency to Voltage Converter

Reference to ground directly with variable reluctance

Op Amp / Comparator with transistor output

50 mA maximum output currents for application directly to the load

Frequency doubling for low ripel

Buid in zener

Linear output ± 0.3%

Application single chip LM2917 Frequency to Voltage Converter

Frequency to Voltage Converter

Rotation speed sensor applications

Speedometer

Tachometer

Cruise Control

Cluth Control

And other applications associated with the measurement of rotation speed or frequency measurements.

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