TREE

As electrolytic capacitors age, their internal resistance, also known as "equivalent series resistance" (ESR), gradually increases. This can eventually lead to equipment failure. Using this design, you can measure the ESR of suspect capacitors as well as other small resistances. Basically, the circuit generates a low-voltage 100kHz test signal, which is applied to the capacitor via a pair of probes. An op amp then amplifies the voltage dropped across the capacitor’s series resistance and this can be displayed on a standard multimeter. In more detail, inverter IC1d is configured as a 200kHz oscillator. Its output drives a 4027 J-K flipflop, which divides the oscillator signal in half to ensure an equal mark/space ratio. Two elements of a 4066 quad bilateral switch (IC3c & IC3d) are alternately switched on by the complementary outputs of the J-K flipflop. One switch input (pin 11) is connected to +5V, whereas the other (pin 8) is connected to -5V. The outputs (pins 9 & ...

Looking for an efficient USB charger that can operate from a 12V car battery? This unit functions at up to 89% efficiency and can charge USB devices at currents up to 525mA. Best of all, it won’t flatten the battery if it's left permanently connected, as long as you remember to unplug the USB device. There are lots of USB chargers on the market but this device has two stand-out features: high efficiency and low standby current. In fact, its standby current is just 160µA, a figure that’s well below the self-discharge current of most lead-acid batteries. This means that you can leave the device permanently connected and it will not cause that battery to go flat (or at least, not much faster than it would of its own accord). Picture of the project: Why is this useful? Well, in September 2009’s “Ask SILICON CHIP” section, D. E. of Ainslie, ACT asked if it was possible to connect a 12V-to-5V USB charger directly to the battery on a motorbike. His reason for wanting to do this is that ...

Usually, Low-Cost Stereo Level Indicator home stereo power amplifiers don’t have output level indicators . An output power level indicator can be added to each channel of these stereo power amplifiers . As low levels of the output power are not disturbing and damaging to the people, there is no need to add a preamplifier and low-level detector before IC LM3915. But you should know when the output power becomes considerably high. Here we present a very simple, low-cost stereo-level indicator circuit for home power amplifiers with power rating of around 0.5W. The circuit is built around two LM3915 dot/bar display driver ICs (IC1 and IC2). LM3915 senses analogue voltage levels to drive ten LEDs, providing a logarithmic 3dB/step analogue display. Stereo Level Indicator Circuit Diagram The voltage levels below 1V are not important because these correspond to a low level of the audio signal. Similarly, input voltage levels above 30V correspond to too high levels of the output power, which ...

Low Voltage Cut-Out Circuit diagram. This circuit will detect when the voltage of a 12v battery reaches a low level. This is to prevent deep-discharge or maybe to prevent a vehicle battery becoming discharged  to a point where it will not start a vehicle. This circuit is different to anything previously presented. It has HYSTERESIS. Hysteresis is a feature where the upper and lower detection-points are separated by a gap.  Low Voltage Cut-Out Circuit diagram :   Low Voltage Cut-Out Circuit Diagram Normally,  the circuit will deactivate the relay when the voltage is 10v and when the load is removed. The battery voltage will rise slightly by as little as 50mV and turn the circuit ON again. This is called "Hunting." The off/on timing has been reduced by adding the 100u. But to prevent this totally from occurring, a 10R to 47R is placed in the emitter lead. The circuit will turn off at 10v but will not turn back on until 10.6v when a 33R is in the emitter. The value o...

Small and portable unit, Useful for old men and old women This low-cost, general-purpose electronic hearing aid works off 3V DC (2x1.5V battery). The circuit can be easily assembled on a veroboard. For easy assembling and maintenance, use an 8-pin DIP IC socket for TDA2822M. Circuit Diagrams: A Low Cost hearing Aid Schematic Parts: P1 = 10K R1 = 2.2K R2 = 330K R3 = 680R R4 = 33R R5 = 100R R6 = 4.7R R7 = 4.7R R8 = 220R C1 = 0.01uF-10V C2 = 100nF-63V C3 = 47uF-10V C4 = 10uF-10V C5 = 0.01uF-10V C6 = 100uF-10V C7 = 100nF-63V C8 = 100nF-63V D1 = Red LED Q1 = BC547 IC1 = TDA2822M EP1 = Mono Earphone 32R SW1 = On-Off Switch Circuit Operation: In this circuit, transistor Q1 and associated components form the audio signal preamplifier for the acoustic signals picked up by the condenser microphone and converted into corresponding electrical signals. Resistor R5 and capacitor C3 decouple the power supply of the preamplifier stage. Resistor R1 biases the internal circuit of the low-voltage conden...

Many digital code lock circuits have been published in this magazine. In those circuits a set of switches (conforming to code) are pressed one by one within the specified time to open the lock. In some other circuits, custom-built ICs are used and positive and negative logic pulses are keyed in sequence as per the code by two switches to open the lock. Circuit diagram : Simple Low-Cost Digital Code Lock Circuit Diagram A low-cost digital code lock circuit is presented in this article. Here the keying-in code is rather unique. Six switches are to be pressed to open the lock, but only two switches at a time. Thus a total of three sets of switches have to be pressed in a particular sequence. (Of these three sets, one set is repeated.) The salient features of this circuit are: 1. Use of 16 switches, which suggests that there is a microprocessor in-side. 2. Elimination of power amplifier transistor to energise the relay. 3. Low cost and small PCB size. An essential property of this...

Amplifier with digital volume control can we make predictably because the circuit is made simple with just single chip TDA8551. The series of Mini Amplifier With Digital Volume Control is a type BTL amplifier with 1 Watt. Techniques for adjusting the volume in this series has been provided with a pin path control that is controlled by providing an input voltage VCC and GND. The series is also equipped with a selector mute, standby and operating. Mini amplifier with digital volume control schematics

All miniature electronic devices operate off batteries. Some of them need higher than the standard battery voltages to operate efficiently. If the battery of that specific voltage is unavailable, we are forced to connect additional cells in series to step up the DC voltage. Thus, the true meaning of miniaturisation is lost. A simple way to overcome this problem is to employ a voltage doubler, if the device under consideration can operate at a small current. Here we present a low-power voltage doubler circuit that can be readily used with devices that demand higher voltage than that of a standard battery but low operating current to work with. The circuit is quite simple as it uses only a few components. Yet, the output efficiency is 75 to 85 percent along its operating voltage range. The available battery voltage is almost doubled at the output of the circuit. Here IC1 is wired as an astable multivibrator to generate rectangular pulses at around 10 kHz. This frequency and duty cycle of...

This is the simple 4A High-Speed Low-Side Gate Driver Circuit Diagram. The UCC27518 and UCC27519 single-channel, high-speed, low-side gate driver device is capable of effectively driving MOSFET and IGBT power switches. Using a design that inherently minimizes shoot-through current, UCC27518 and UCC27519 are capable of sourcing and sinking high, peak-current pulses into capacitive loads offering rail-to-rail drive capability and extremely small propagation delay typically 17 ns. The UCC27518 and UCC27519 provide 4-A source, 4-A sink (symmetrical drive) peak-drive current capability at VDD = 12 V. The UCC27518 and UCC27519 are designed to operate over a wide VDD range of 4.5 V to 18 V and wide temperature range of -40°C to 140°C. Internal Under Voltage Lockout (UVLO) circuitry on VDD pin holds output low outside VDD operating range. 4A High-Speed Low-Side Gate Driver Circuit Diagram   Features Low-Cost, Gate-Driver Device Offering Superior Replacement of NPN and PNP Discrete Sol...

The TA7066P is original monolithic Intregated Circuit Audio Power Amplifier. Package IC is SIP10-16 and manufactered by TOSHIBA.  The above sequence is a series of low-grade intregated circuit amplifier , which was very small output . But this amplifier is very high impedance power output. For more details , see description below. Technical information : Min. Voltage   : 8   Volts DC Max. Voltage  : 25 Volts DC Max. Power    : 0,3 Watts Impedance      : 150 Ohms Min. Currents : 2,8 mA

Here i share power amplifier based on IC TDA7236 . This amplifier require minimum voltage 0,9 volt and maximum voltage is 1, 6 volt , its very low voltage amplifier. You can use this amplifier everywhere just with one battery 1,5 volt. Power output 16 mW with 32 ohms impedance. see circut below :

FEATURES 2 STEREO INPUT 1 STEREO OUTPUT TREBLE BOOST BASS CONTROL BASS AUTOMATIC LEVEL CONTROL VOLUME CONTROL IN 1dB STEPS MUTE STAND-BY FUNCTION SOFTWARE CONTROLLED ALL FUNCTION ARE PROGRAMMABLE VIA SERIAL BUS Circuit Diagram: Circuit diagram for Low voltage analog audio processor  Datasheet for TDA7469: Download

This circuit allows a 240V mains appliance to be controlled remotely via low-voltage cabling and a pushbutton switch. The mains appliance (in this case, a light bulb) is switched with a suitably-rated relay . All of the electronics is housed in an ABS box located in proximity to the appliance. The pushbutton switch and plugpack are located remotely and can be wired up with 3-core alarm cable or similar. Cable lengths of 20m or more are feasible with this arrangement. When the switch (S1) is pressed, the input (pin 8) of IC1c is briefly pulled low via the 10mF capacitor, which is initially discharged. Low-Voltage Remote Mains Switch Circuit diagram: Low-Voltage Remote Mains Switch Circuit Diagram The output (pin 10) immediately goes high and this is inverted and fed back to the second input (pin 9) via another gate in the quad NAND package (IC1d). In conjunction with the 1MW resistor and 470nF capacitor, IC1d eliminates the effects of contact "bounce" by ensuring that IC1c’s o...

Here is the circuit diagram of a low cost universal charger for NiCD - NiMH batteries. This circuit is Ideal for car use. It has ability to transform a mains adapter in to a charger . This one can be used to charge cellular phone, toys, portables, video batteries, MP3 players, ... and has selectable charge current. An LED is located in circuit to indicate charging. Can be built on a general purpose PCB or a veroboard. I hope you really like it. Picture of the circuit:     A Low Cost Universal Charger Circuit Schematic Circuit diagram: A Low Cost Universal Charger Circuit Diagram Parts: R1 = 120R-0...5W R2 = See Diagram C1 = 220uF-35V D1 = 1N4007 D2 = 3mm. LED Q1 = BD135 J1 = DC Input Socket Specifications: Ideal for in car use. LED charge indication. Selectable charge current. Charges Ni Cd or NiMH batteries. Transforms a mains adapter into a charger. Charge cellular phone, toys, portables, video batteries … Features: LED function indication. Power supply polarity prot...

You feel confused to detect wether a battery is low or high, or you want to be notified if the battery and has expired , this circuit can detect if a battery has begun to decrease its strength. Circuit is based on LM4250 IC is able to detect if the battery runs out and will issue a notification signal.

Low pass filter is a low-pass filter with low frequency signals but attenuates (reduces the amplitude of) signals with frequencies higher than cutoff frequency. The actual amount of damping for each frequency varies from filter to Filtering. Sometimes called-high-cut filter, or treble cut filter when used in audio applications. Low-low pass filter is the opposite of the band-pass filter. Low Pass Filter Basic Circuit The concept of low-pass filter exists in many forms, including electronic circuits (like a hiss filter used in audio), digital algorithms for smoothing data sets, acoustic barriers, blurring the image, and so forth.

This is simple electronic Circuit Diagram Project of Low Light Level Drop Detector. This self-biasing configuration is useful any time srnall changes in light level must be detected, for example, when monitoring very low flow rates by counting drops of fluid. In this bias method, the photodarlington is de bias stabilized by feedback from the collector, compensating for different photodarlington gains and LED outputs. The 10-I`F capacitor integrates the collector voltage feedback, and the 10-MO resistor provides a high base-source impedance to minimize effects on optical performance. Low Light Level Drop Detector Circuit Diagram: The detector drop causes a momentary decrease in light reaching the chip, which causes collector voltage to momentarily rise, generating an output signal. The initial light bias is small because of output power constraints on the LED and mechanical spacing system constraints. The change in light level is a fraction of this initial bias because of stray light pa...

The 32-kHz low-power clock oscillator offers numerous advantages over conventional oscillator circuits based on a CMOS inverter. Such inverter circuits present problems, for example, supply currents fluctuate widely over a 3V to 6V supply range, while current consumption below 250 µA is difficult to attain. Also, operation can be unreliable with wide variations in the supply voltage and the inverter’s input characteristics are subject to wide tolerances and differences among manufacturers. The circuit shown here solves the above problems. Drawing just 13 µA from a 3V supply, it consists of a one-transistor amplifier/oscillator (T1) and a low-power comparator/reference device (IC1). The base of T1 is biased at 1.25 V using R5/R4 and the reference in IC1. T1 may be any small-signal transistor with a decent beta of 100 or so at 5 µA (defined here by R3, fixing the collector voltage at about 1 V below Vcc). The amplifier’s nominal gain is approximately 2 V/V. The quartz crystal combined wi...

Amplifier circuit below represents a very small amplifier circuit output. Maximum output is no more than 1W, comprehension is low but received a series of sensitive enough, and power amplifier circuit is very suitable for use in radio receiver, especially on FM radio. Technical information. Minimum Voltage = 4 Volt DC Maximum Voltage = 15 Volt DC Power Output         = 0,325 W RL                          = 8 Ohm Ft                            = 40Hz - 18KHz Icco                        = 6mA Part List : R1 = 100K R2 = 2,7R R3 = 1K C1 = 100uF C2 = 220uF C3 = 47uF C4 = 0,01uF

The circuit of battery indicator consists of a 741 operational amplifier configured as a voltage comparator, using a zener diode as a reference voltage pattern. This circuit can be adapted to work with battery between 6 and 18 V, and the only changes required would be a lower Zener voltage and current limit resistor in the case of low voltage below 9 V and greater for higher voltages.The adjustment is made with R2 which can be a trim pot. Dimmable Low Battery Indicator Circuit Diagram