TREE

This tiny conductivity tester works with LM 3909. The tester makes a beeping sound if the resistance between the test probes between 0 and 100 O lies. Due to the volume of the beep, the resistance between the test probes can be determined. Audio Lm 3909 IC-conduction tester Circuit Diagram Parts List      R1 = 1 k      C1 = 10 uF      C2 = 100 nF      LS = Loudspeaker 12 to 16 Ω      IC1 = LM 3909

Simple Water Alarm Circuit Schematic .The LM1830 fluid detector IC from National Semiconduc tor is designed to be able to detect the presence of fluids using a probe. This chip requires a relatively high supply voltage and is not the most frugal power consumer. It is also quite specialised so unless you are buying in bulk the one-off price is not cheap.  An alternative circuit show n her e uses a standard CMOS IC type 74HC14. It has the advantage of operating with a 3 V supply and consumes less than 1 µA when the alarm is not sounding, this makes it ideal for use with batteries.  Water Alarm Schematic Circuit Diagram The 74HC14 has six inverters with hysteresis on their input switching thresholds. A capacitor (C1) and a feedback resistor (R1) is all that’s necessary to make an inverter into a square wave signal generator.  In the water alarm circuit the feedback resistor consists of R1 and the water sensor in series. R1 prevents any possibility of short-circuit between t...

This is a simple Pre-Amplifier Circuit Diagram . This simple circuit contribute best gain to weak audio signals. use it in front of an RF oscillator to make an RF transmitter that is very sensitive to sound. Best Pre-Amplifier Circuit Diagram

Description This is a portable battery powered USB charger circuit. This circuit is able to charge your PDAs, Ipods, Mp3 players and any device that plug in to a computer USB to charge. If you fit this circuit in a small box with a 9V battery then it will become a portable emergency USB charger. The schematic is so simple using only few components so you can make this circuit in some minutes if all parts available with you. The circuit is using low dropout regulator IC LM7805 which is easily available in the market and it is also very cheap. The circuit takes voltage from 9V battery and step down the voltage in to a DC 5V output.  Circuit Diagram  Source- http://circuitdiagram.org/usb-charger.html

Build a Square A to Sine Wave Converter Circuit Diagram. This is a simple circuit diagram in this circuit using Two pairs of MOSFETs form a bridge that alternately switches current in opposite directions. Two parallel-resonant LC circuits complete the converter. The Ll/C1 combination is resonant at the fundamental frequency; the L2/C2 combination is resonant at the clock frequency`s third harmonic and acts as a trap.  Square A to Sine Wave Converter Circuit Diagram Tl and C3 ensure that both halves of the MOSFET bridge are never on at the same time by providing a common delay to the gate drive of each half. Select the values of R1 and C3 to yield a time constant that`s less than 5% of the clock`s period. You can add an output amplifier for additional buffering and conditioning of the circuit`s sine-wave output.

Dual Power Supply Circuit For Amplifiers . A power supply suitable for use with the 60W amplifier presented in the predefining project is perfectly simple, and no great skill is required to build (or design) one.  There are a few things one should be careful with, such as the routing of high current leads, but these are easily accomplished. The first thing to choose is a suitable transformer.  I suggest toroidal transformers rather than the traditional "EI" laminated types because they radiate less magnetic flux and are flatter, allowing them to be installed in slimmer cases.  They do have some problems, such as higher inrush current at switch on, which means that slow blow fuses must be used. For the 60W amplifier, a nominal (full load) supply of +/- 35V is required, so a 25-0-25 secondary is ideal - however, see Updates, below.  The circuit for the supply is shown below, and uses separate rectifiers, capacitors and fuses for each channel.  Only the transformer...

This is a simple Project of 12 V AC Dimmer Circuit Diagram. 12-V AC Dimmer Circuit Diagram The circuit described here is derived from a conventional design for a simple lamp dimmer, as you can see if you imagine a diac connected between points A and B. The difference between this circuit and a normal diac circuit is that a diac circuit won’t work at 12 V. This is the fault of the diac. Most diacs have a trigger voltage in the range of 30 to 40V, so they can’t work at 12 V, which means the dimmer also can’t work. 12-V AC Dimmer Circuit Diagram The portion of the circuit between points A and B acts like a diac with a trigger voltage of approximately 5.5 V. The network formed by R1, P1 and C1 generates a phase shift relative to the supply voltage. The ‘diac equivalent’ circuit outputs a phase-shifted trigger pulse to the triac on each positive and negative half-cycle of the sinusoidal AC voltage. This works as follows. First consider the positive half of the sine wave. C1 charges when the...

The strength supply routine structure is developed as a resource of continuous present with adverse heat range coefficient. Transistor Q1 (BD 140) is used as a heat range indicator. transistor Q2 is used to avoid the strength supply from discharging through R1 when strength is out of stock. Getting routine is developed depending on the LM350 present regulator IC. The result present of the battery charger can be altered between 13-15 V by various the POT R6. LM350 will try to keep the present decrease between the feedback pin and result pin at a continuous value of 1.25V. So there will be a continuous present circulation through resistor R1. Q1 act here as a heat range indicator with the help of R6/R3/R4 elements that are more or less manages the platform present of Q1. As relationship emitter / platform of transistor Q1, the same as other semiconductors, containing the heat range coefficient of-2mV / ° C, the present result will also display a bad heat range coefficient. This one is ju...

This is an automatic emergency lamp with day light sensing, means it senses darkness/night and turns ON automatically. Similarly it senses day light and turns OFF automatically. A simple emergency lamp which does not require any special equipment; even a multimeter to assemble and use. Any individual who can do a good quality soldering must be able to build this circuit successfully. This can be easily accommodated in the defunct two 6 watt tube National Emergency Lamp or any PL tube type emergency lamp. The difference will be in the working; it will work non stop for more than 8 hours.deep discharge is taken care by the LED characteristic and over charge protection is taken care by the fixed voltage regulator.This uses a simple 3Pin fixed regulator which has a built in current limiting circuit. The only required adjustment is the preset which has to be set to ensure the LEDs just light up (it should be left at that position). The 5mm LDR is just mounted on top of the emergency light a...

This is the simple Using TDA1562Q 54 W Amplifier Circuit Diagram. The integrated output amplifier described in this article consists of little more than one integrated circuit. It is intended especially for use in motor vehicles and other battery operated applications. Although it appears simple and hardly worth looking at, the amplifier can produce an appreciable audio power output.[link] Using TDA1562Q 54 W Amplifier Circuit Diagram D ata PropertiesHigh power output through Class-H operation Low power dissipation during reproduction of music signals Proof against short-circuits Protection against excessive temperatures Standby switch No power-on or power-off clicks Visible error indication Measurement results (at Ub=14.4 V) Supply voltage 8–18 V Sensitivity 760 mV r.m.s. Input impedance 70 kΩ Power output 54 W r.m.s. into 4 Ω (f=1 kHz; THD+N=1%) Harmonic distortion (THD+N) at 1 W into 4 Ω: 0.046% (1 kHz) 0.29% (20 kHz) at 35 W into 4 Ω: 0.12% (1 kHz) 0.7% (20 kHz) Signal-to-noise rat...

Fan Controller Using Just Two Component Circuit diagram. The Maxim MAX 6665 (www.maxim-ic.com) provides a complete temperature-dependent fan controller. It can switch fans operating at voltages of up to 24 V and currents of up to 250 mA. The IC is available from the manufacturer in versions with preset threshold temperatures between +40 °C (MAX6665 ASA40) and +70 °C (MAX6665 ASA 70). The device’s hysteresis can be set by the user via the HYST input, which can be connected to +3.3 V, connected to ground, or left open. The following table shows the hysteresis values available: HYST = Hysteresis open = 1 °C ground = 4 °C +3.3V = 8 °C Fan Controller Using Just Two Component Circuit diagram: Fan Controller Circuit Diagram The other pins of the SO8 package are the FORCEON input and the status outputs WARN, OT and FANON. The test input FORCEON allows the fan to be run even below the threshold temperature. The open-drain output WARN goes low when the temperature rises more than 15 °C above th...

Tini Amplifier with 3 Transistor Circuit Diagram . This is a very small or mini amplifier circuit with 3 transistor . This simple mini amplifier 50mW power drawn by 3 transistor. The series of three mini-amplifier transistors can be used for loud speaker 8 ohm load. Source voltage required to activate the mini-amplifier can be drawn from the batteries 9V. 3 transistor amplifier is often used in simple portable audio devices such as radios or small tape recorder. Mini-transistor amplifier circuit 3 is quite simple as shown in the figure below. Tini Amplifier with 3 Transistor Circuit Diagram Mini-transistor amplifier circuit 3 includes type of amplifier OTL (Output Transformer Less). Mini-transistor amplifier circuit 3 is used for output coupling capacitors. Amplifier circuit is simple and suitable when used for audio amplifier experiment.

This the simple electronic Inverting Power Supply Circuit Diagram. This circuit will provide a negative dc voltage that is approximately equal to the positive input voltage at no load and about 3 V less at 10 mA load. -`~ is from +5 to +15 Vdc. Do not exceed 15 V or Ul might be damaged.  Simple Inverting Power Supply Circuit Diagram

Detects if a device is not properly connected to its supply Suitable for battery chargers, portable appliance supplies etc. The above circuit can be useful to detect if the load of any battery charger or plug-in adapter supply is not properly connected. The load can be a set of batteries to be charged or any other type of battery or low dc voltage operated device. The circuit can safely operate over a 3 to 15V range and 1A max. Current, provided the supply voltage is about one volt higher than the voltage required by the load. The circuit is inserted between the supply and the load; therefore, until a trickle-charging current of at least 100µA is flowing towards the load, D1 and D2 will conduct. The forward voltage drop (about 1V) available across the Diodes drives Q2 into conduction and, consequently, Q1 will be cut-off. If no appreciable load is connected across the circuit's output, Q2 will become cut-off, Q1 will conduct and the Piezo-sounder will beep. Circuit diagram: Broken...

TDA1308T Headphone amplifier circuit  TDA1308T Headphone amplifier circuit

dual BTL 14 watt audio amplifier circuit Datasheet for AN7176: Download

This circuit shows how to build a super-sensitive, mini-powered FM transmitter consisting of a RF (radio Frequency) oscillator section interfaced with a high sensitivity, wide pass-band audio amplifier and capacitance mike with a built-in FET (Field Effect Transistor) that modulates the base of the RF oscillator transistor. Transistor Q1 forms a relatively stable RF oscillator whose frequency and is determined by the value of coil L1 and turning capacitor C4. Part List : R1_______15K R2_______3K9 R3_______220R R4,R5____1K R6,R9____10K R7_______390K C1,C6____0.01uF C2_______4.7pF C3_______0.1uF C4_______6-35pf trimmer cap C5_______2.2uF B1_______3V L1_______Coil winding (see below) Q1,Q2____PN2222 M1_______Special FET bypassed microphone Assemble L1 : Form L1 by tightly wrapping eight turns of #16 bus wire on a #8 wood screw. Produces an eight-turn coil with an inner diameter of approximately 0.135 inches and lenght of about 0.625 inches. Insert in the proper hole and solder as shown.

This is the Simple Over Voltage Protector Circuit Diagram. The whole circuit of over voltage protector is build and fabricated around operational amplifier used as comparator. The inverting input is given to pin 2 of op-amp IC (IC1) with reference voltage of 5.1V from zener diode. Similarly, non-inverting input is given to pin no 3 of IC1 use as sensor for over voltage protector for sensing voltage fluctuation in the mains. The two transistors T1 and T2 conduct alternating (i.e. one at a time) according to the voltage of mains. Simple Over Voltage Protector Circuit Diagram When voltage is around or below 240V AC transistor T1 is in off-state where T2 energized relay RL1. Similarly, when voltage becomes beyond 240V (i.e. above 240V) T1 is in conducting-stage and T2 is in off-stage which de-energized the relay RL1 and switch-off the appliance. PARTS LIST Resistors (all ¼-watt, ~+mn~ 5% Carbon) R1 = 147 Ω/2W R2 = 100 Ω/1W R3 = 330 Ω R4 = 100 KΩ R5 = 1.8 KΩ R6, R7 = 1 KΩ VR1 = 10 KΩ VR2 = ...

This is a simple power on switching circuit . This type of reset pulse is ideally provided by this circuit. Because of the high input impedance of the Schmidt trigger, long reset pulse times may be achieved without the excess dissipation that results when both output devices are on simultaneously, as in an ordinary gate device (B). A reset pulse is often required at power-on in a digital system. See circuit diagram below. Simple Power On Reset Circuit Diagram

circuit diagram: A total of four 1.2V cells are used here. Resistor R2 limits the charging current. For charging Li-ion battery (used in mobile phones), shift switches S1 and S2 to ‘on’ position and use connector ‘C.’ Regulator IC 7805 (IC2) provides 5V for charging the Li-ion battery. Using this circuit, you can charge a 3.6V Li-ion cell very easily. Resistor R3 limits the charging current. Fig. 2 shows the circuit for a small LED-based lamp. It is simple and low-cost. Six 10mm white LEDs (LED2 through LED7) are used here. Just connect them in parallel and drive directly by a 3.6V DC source. You can use either pencil-type Ni-Cd batteries or rechargeable batteries as the power source. Assemble the circuit on a general-purpose PCB and enclose in a small box. Mount RCA socket on the front panel of the box and wire RCA plug with cable for connecting the battery and LED-based lamp to the charger.