Schematic Diagram

Do you looking for the function of IC LM35 ? The works of IC LM 35 typically serves as a temperature sensor. IC LM 35 is packaged in the form of integrate circuit which prisoners rates is a function of temperature, the temperature will cause a change of IC LM 35.

Heat energy from the electrodes will cause the IC LM 35 temperature changes that subsequently alter rates prisoners, the characteristics of this sensor is linear to temperature changes means that, if the temperature changes that tend to increase the temperature of the IC will also rise, as well as if the temperature falls.

Images and physical shape of IC LM35

The voltage output from these sensors is ± 10 mu/0C every 10C temperature rise and the largest range of temperatures - 550C to 1150C.

Description               Circuit showing a Burglar Alarm.Here we have used a ldr and a switching transistor for making this circuit
.When the light coming towards the ldr during the period the ldr have low resistance so the buzzer will on.When the light going away the ldr during the period the ldr have high resistance so the transistor will off.Here you need a 12 volt power supply

 Components Required      Resistor

                   10 k(preset)

      Transistor
                   BC 548

       LDR
        Buzzer

Source by : http://www.electronics-circuits.in/2012/03/burglar-alarm-ldr-bc-548.html

Firstly, Id like to stress that the intended use of this circuit is only one of many possible applications. Apart from the obvious usage as a headphone amplifier, the circuit can be used for a range of applications where a wide bandwidth low power amplifier is needed. Some of the options include ...

• Reverb drive amplifier - ideal for low and medium impedance reverb tanks
• High current line driver - suitable for very long balanced lines
• Low power speaker amplifier - better performance than small integrated amps
• ... and of course, a headphone amp.

In short, the amp can be used anywhere that you need an opamp with more output current than normally available. Since most are rated for around ±20-50mA, general purpose opamps are not suitable for driving long cables or anywhere else that a relatively high output current is needed.

As a headphone amplifier, this design is very similar to others on the ESP site, but the main difference is that this one (and P70) has been built and fully tested. The design is fairly standard, and every variation was checked out before arriving at the final circuit. A photo of the prototype is shown below, and at only 64 x 38mm (2.5 x 1.5 inches) it is very small - naturally, the heatsink is not included in the dimensions.

The amplifier is capable of delivering around 1.5W into 8 ohm headphones, and 2.2W into 32 ohms - this is vastly more than will ever be needed in practice. The use of a 120 Ohm output resistor is recommended, as this is supposed to be the standard source impedance for headphones. Unfortunately, many users have found that their phones perform better when driven from a low impedance source.


The circuit is based on an opamp, with its output current boosted by a pair of transistors. Distortion is well below my measurement threshold at all levels below clipping into any impedance. Noise is virtually non-existent - even with a compression driver held to my ear, I could barely hear any, and I couldnt hear any with headphones.

WARNING
Headphones are rated in dB SPL at 1mW, and this amplifier (like many other similar headphone amps) is capable of producing extreme SPLs. The levels obtainable are sufficient to cause almost instantaneous permanent hearing damage! Never operate the amp at very high levels, and never switch the amplifier on with signal while wearing you headphones.

Always start with the volume control at minimum, and gradually increase the level until it is comfortable, but not too loud. Because of the very low distortion, it is easy to increase the level too far without noticing. Your ears are precious - safeguard them at all times.

Note the warning above - this is serious. Most headphones are capable of at least 94dB SPL at 1 mW, with some as high as 107dB SPL. Even 10mW is enough to create sound levels capable of causing hearing damage, so you must be very careful to avoid damaging levels.

Table 1 - Maximum Exposure to SPL
Note that the exposure time is for any 24 hour period, and is halved for each 3dB SPL above 85dB. The above shows the accepted standards for recommended permissible exposure time for continuous time weighted average noise, according to NIOSH (National Institute for Occupational Safety and Health) and CDC (Centers for Disease Control). Although these standards are US based, they apply pretty much equally in most countries - hearing loss does not respect national boundaries.

Description

The amplifier itself is fairly conventional, and is very similar to another shown on this site (see Project 24). This amplifier does not include the active volume control, because in general it is far easier to get a good log pot (or simply fake the pots law as described in Project 01). Likewise, it does not include the cross-feed described in Project 109. If this is desired, it is very easy to implement on a small piece of tag board, or even sky hook the few components off the bypass switch. Full details of how to do this will be included in the construction guide when PCBs are available.

The output transistors are biased using only resistors, rather than constant current sources. Extensive testing showed that using current sources made no discernible difference to performance, but increased the complexity and PCB size. Using separate caps for each biasing diode does make a difference though - and although it is relatively minor, the use of the two caps is justified IMHO.

The bias diodes should be 1N4148 or similar - power diodes are not recommended, as their forward voltage is too low. This may result in distortion around the crossover region, where one transistor turns off and the other on. As shown, crossover distortion is absolutely unmeasurable with the equipment I have available.

Figure 1 - Headphone Amplifier Circuit Diagram

Above is the schematic of one channel. Resistors and caps use the suffix R for the right channel. The second half of the dual opamp powers the right channel. Note that the volume control shown is optional, and is not on the PCB. If needed, it may be mounted in a convenient location and the output connected to the inputs of the board as shown. D1 and D2 (L and R) are 1N4148 or similar.

One of the reasons the amp is so quiet is that the entire board runs from a regulated supply, so hum (in particular) is eliminated. Although an unregulated supply can be used, this is not recommended. The supply should be separate from that used for your preamp, because of the relatively high current drawn by the amplifier (at least with low impedance phones). A P05 preamp supply can be used, and will ensure optimum performance.

The prototype amplifier has flat frequency response from 10Hz to over 100kHz. Distortion is below my measurement threshold with any level or load impedance, and output impedance is almost immeasurably low. Your headphones may be designed to operate from a 120Ω source impedance (many are), so this may be added if it improves sound quality. Adding any series resistance will reduce the available power, but it is already far greater than you can use. Without series resistance, the minimum power into various load impedances is given below (based on ±15V supplies).

Continuous dB SPL	Maximum Exposure Time
85	8 hours
88	4 hours
91	2 hours
94	1 hour
97	30 minutes
100	15 minutes
103	7.5 minutes
106	<4 minutes
109	<2minutes
112	~ 1 minute
115	~ 30 seconds

Impedance	Power (Direct)	120 Ohm Feed
8 Ohms	1.5 W	35 mW
32 Ohms	2.2 W	99 mW
65 Ohms	1.1 W	136 mW
120 Ohms	595 mW	149 mW
300 Ohms	238 mW	121 mW
600 Ohms	119 mW	82 mW

Table 2 - Output Power Vs. Impedance
This is not especially comprehensive, but will cover the majority of headphones in common use. In all cases, the available power is more than needed ... not so you can damage your hearing, but to allow adequate headroom for transients.

Construction

While it may be possible to build it using Veroboard or similar, there is a high risk that it will oscillate because of the very wide bandwidth of the amplifier. A capacitor may be added in parallel with R4 (L and R) to reduce the bandwidth if stability problems are encountered. Although I used an NE5532 opamp for the prototype, the circuit will also work with a TL072, but at reduced power. You may also substitute an OPA2134 or your favorite device, taking note of the following ...
The standard pinout for a dual opamp is shown on the left. If the opamps are installed backwards, they will almost certainly fail, so be careful.

The suggested NE5532 opamp was used for the prototype, and performance is exemplary. Devices such as the TL072 will be quite satisfactory for most work, but if you prefer to use ultra low noise or wide bandwidth devices, that choice is yours.

Construction is fairly critical. Because of the wide bandwidth of the NE5532 and many other audio grade opamps, the amplifier may oscillate (the prototype initially had an oscillation at almost 500kHz), so care is needed to ensure there is adequate separation between inputs and outputs. Even a small capacitive coupling between the two may be enough to cause problems.

As shown in the photo, this amplifier needs a heatsink. While it can operate without one at low power using high impedance headphones, you need to plan for all possibilities (after all, you may purchase low impedance phones sometime in the future). The heatsink does not need to be massive, and the one shown above is fine for normal listening levels. An aluminium bracket may be used to attach to the chassis - I recommend 3mm material. Note that the heatsink should always be earthed (grounded).

The output transistors must be insulated from the heatsink. Sil-Pads™ are quite suitable because of the relatively low dissipation, but greased mica or Kapton can be used if you prefer. If you use the suggested 3mm aluminium, you can drill and tap threads into the heatsink, removing the need for nuts.

Testing

Connect to a suitable power supply - remember that the supply earth (ground) must be connected! When powering up for the first time, use 56 ohm "safety" resistors in series with each supply to limit the current in case you have made a mistake in the wiring. These will reduce the supply voltage considerably because of the bias current of the output transistors.

If the voltage at the amplifier supply pins is greater than ±6V and the output voltage is close to zero, then the amplifier is probably working fine. If you have an oscilloscope, check for oscillation at the outputs ... at all volume control settings. Do this without connecting your headphones - if the amp oscillates, it may damage them.

Once you are sure that all is well, you may remove the safety resistors and permanently wire the amplifier into your chassis.

We published a design for a stereo microphone preamplifier with balanced inputs and a phantom power supply. The heart of this circuit was a special Analog Devices IC, the SSM2017. Unfortunately, this IC has been discontinued. In its place, the company recommends using the pin-compatible AMP02 from its current product line. However, and again unfortunately, the specifications of this opamp make it considerably less suitable for use as a microphone amplifier. By contrast, Texas Instruments (in their Burr Brown product line) offer an integrated instrumentation amplifier (type 1NA217) that has better specifications for this purpose.


Incidentally, this IC is also recommended as a replacement for the SSM2017. It features internal current feedback, which ensures low distortion (THD + noise is 0.004 % at a gain of 100), low input-stage noise (1.3 nV/√Hz) and wide bandwidth (800 kHz at a gain of 100). The supply voltage range is ±4.5 V to ±18 V. The maximum current consumption of the 1NA217 is ±12 mA. The gain is determined by only one resistance, which is the resistance between pins 1 and 8 of the IC. The circuit shown here is a standard application circuit for this instrumentation amplifier. R1 and R2 provide a separate phantom supply for the microphone connected to the amplifier (this is primarily used with professional equipment).



This supply can be enabled or disabled using S1. C1 and C2 prevent the phantom voltage from appearing at the inputs of the amplifier. If a phantom supply is not used, R1 and R2 can be omitted, and it is then better to use MKT types for C1 and C2. Diodes D1–D4 are included to protect the inputs of the 1NA217 against high input voltages (such as may occur when the phantom supply is switched on). R4 and R5 hold the bias voltage of the input stage at ground potential. The gain is made variable by including potentiometer P1 in series with R6. A special reverse log-taper audio potentiometer is recommended for P1 to allow the volume adjustment to follow a linear dB scale.

The input bias currents (12 µA maximum!) produce an offset voltage across the input resistors (R4 and R5). Depending on the gain, this can lead to a rather large offset voltage at the output (several volts). If you want to avoid using a decoupling capacitor at the output, an active offset compensation circuit provides a solution. In this circuit, a FET-input opamp with a low input offset (an OPA137) is used for this purpose. It acts as an integrator that provides reverse feedback to pin 5, so the DC output level is always held to 0 V. This opamp is not in the audio signal path, so it does not affect signal quality. Naturally, other types of low-offset opamps could also be used for this purpose. The current consumption of the circuit is primarily determined by the quiescent current of IC1, since the OPA137 consumes only 0.22 mA.

This circuit automatically turns a motor cycles headlight on and off, independently of both the light and ignition switches, provided the battery is fully charged. The first stage uses the 22O resistor and ZD1 to hold transistor Q1 off while the motor is not running; it draws about 2mA. Once the battery voltage exceeds 7.0V during charging, Q1 begins to turn on.

The last stage uses the 22O resistor and ZD2 to turn on transistor Q2, which pulls the base of Q1 down, switching it hard on. In conjunction with the Vbe drop of Q2, ZD2 will turn off Q2 at a battery voltage of about 6.7V. In practice, this means that the headlight will be on most of the time while the motor is running and charging the battery. Heatsinks are required for both transistors. The circuit can be mounted adjacent to the battery with a single lead going to the headlight power feed.

Circuit diagram:
Parts:

P1 = 5R - 3W
R1 = 220R -1W
R2 = 1R - 1W
R3 = 22R - 5W
R4 = 22R - 5W
Q1 = BD139
Q2 = MJ4502
D1 = 6.2V - 1WZener
D2 = 6.2V - 1WZener
B1 = 6.6V - 7.2V
F1 = Fuse 15A
LP1 = DIP Beam 6V-25W Halogen

Do you drive an older car without an automatic "lights-on" warning circuit? If so, youve probably accidentally left the lights on and flattened the battery on one or more occasions. This headlights reminder circuit will prevent that. Its more complicated than other circuits but its also more versatile. As shown, the circuit uses two low-cost ICs. IC1 is a 555 timer which is wired to operate in astable mode. Its output clocks IC2, a 4017B decade counter. IC2 in turn drives a row of indicator LEDs and also resets IC1 (after about 10s) via transistor Q2.

The circuit works like this:

when the ignition is on, transistor Q1 is also on and this pulls pin 4 of IC1 low. As a result, IC1 is held reset and no clock pulses are fed to IC2. Conversely, if the ignition is turned off, Q1 will turn off and so IC1 will start oscillating and sound the piezo siren. At the same time, IC1 will clock IC2 and so LEDs 1-10 will light in sequence and stop (after about 10s) with the last LED (LED10) remaining on. Thats because, when IC2s O9 output (ie, pin 11) goes high, Q2 also turns on and this pulls pin 4 of IC1 low, thus stopping the oscillator (and the siren).

Circuit diagram:
Note:

That different colored LEDs are used to make the display look eye-catching but you make all LEDs the same color if you wish. Installing optional diode D1 will alter IC1s frequency and this will alter the display rate. Finally, if the lights are turned off and then back on again, the alarm will automatically retrigger. LED1 is always on if the lights are turned on. If you dont want the LED display, just leave the LEDs out.

The Solar Panel

To accomplish our iPod solar charger we acclimated a 250mA 6 Volt Solar Console (available in the REUK Shop). Alike in the brightest sunshine the voltage is not badly aloft that of the iPod battery, and the accepted is affluence abundant to allegation the array in a few hours in ablaze altitude (even in the UK!).

A blocking diode should be acclimated (in the absolute solar console lead) to anticipate the iPod array from boring clarification at night if it is still affiliated to the panel. Unforunately this after-effects in up to 0.7 Volts actuality absent as calefaction in the diode, so it can be larboard out if you adopt to accept a faster charger which will allegation the array in lower ablaze conditions.

Note that abounding solar panels are supplied with a branch adapted blocking diode.

Voltage Regulator

...where R1 is a 270 Ohm resistor, and R2 is theresistor used to set the output voltage according to the following equation:

Since our desired charging voltage is 5 Volts, we see that ideally R2 would be 270 * ((5/1.25) -1) = 810 Ohms. This is not a standard resistor size, however we had an 820 Ohm resistor which should result in an output voltage of 5.05 Volts.

Wiring up the aloft ambit on a prototyping breadboard with a 270 Ohm R1 resistor, and 820 Ohm R2 resistor we can affirm that the achievement voltage is 5.06 Volts - absolute for our iPod charger. It is capital to analysis that the achievement voltage is about 5 Volts application a acceptable multimeter afore attempting to allegation your iPod or the array and/or iPod itself could be damaged.

iPod Solar Charger Prototyping

Connecting the Charger to the iPod

The following schematic depicts the Morris Minor Wiring Diagram and Cable Color Code. This wiring diagram and electric circuit schematic apply for Morris Minor Series MM, Series II and Series 1000. (click image to enlarge)

Key to Wiring Diagram

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Alternator – 11 AC Charging Warning Light Fuse Unit Fuel Pump Ignition and Starter Switch Stop Lamp Switch R.H. Stop Lamp L.H. Stop Lamp Ignition Coil Distributor Control Unit – 4TR Interior Light and Switch Courtesy Light Switch Courtesy Light Switch Instrument Voltage Stabilizer Fuel Gauge Fuel Tank Unit Heater Switch Heater 12-Volt Battery Starter Solenoid Switch Starter Motor Horn Horn-push Oil Filter warning Light and Switch Oil Pressure Warning Light  R.H. Front Flasher R.H. Rear Flasher Lighting Switch

30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

Main Beam Warning Light R.H. Headlamp Main Beam Line Fuse (10 Amp) Panel Light Switch Panel Light Panel Light Flasher Switch L.H. Rear Flasher L.H. Front Flasher L.H. Headlamp Main Beam R.H. Headlamp Dip Beam L.H. Headlamp Dip Beam Dipper Switch Flasher Unit Flasher Warning Light L.H. Pilot Lamp R.H. Pilot Lamp R.H. Tail Lamp L.H. Tail Lamp Number-Plate Lamp Number-Plate Lamp Windscreen Wiper Switch and Motor Snap Connectors Terminal Blocks or Junction Box Earth Connections Made via Cable Earth Connections Made Relay – 6RA Warning Light Unit – 3AW Ammeter

Wiring and Cable Color Code

B – Black U – Blue N – Brown

G – Green P – Purple R – Red

W – White Y – Yellow D – Dark

W – White Y – Yellow D – Dark

When a cable has two color code letters, the first denotes the main color and the second denotes the tracer color.

There are many occasions when a switching delay is required. One way of achieving this is to use an RC network and an inverter (see figure 1).
This is quite practical and obvious as there are nearly always some gates Ieft over in a circuit. Unfortunately, every electronic component has a definite tolerance and so it is virtually impossible to determine the delay precisely in advance. However a considerable improvement can be achieved by connecting two inverter/ RC networks in series as shown in figure 3. The nominal threshold voltage of the inverter in figure ‘l is half the supply voltage and has a tolerance of 1 30%. Figure 2 shows the signal input to 1 the gate. lf this input is between UC 0.35 Ub and UC = 0.65 Ub the inverter may consider it either logic _ 0’ or ll These voltages occur when a capacitor is charged through a resistor after a period of 0.43 ·r and I l.05r respectively. (r is the time constant of the circuit and is equal to R x C). The nominal threshold voltage UC = 0.5 Ub is reached after a time of t = 0.69 r. lf the two inverters and RC networks of figure 3 are used, each RC net· work must produce the same delay, equal to half the total value of figure l.

The total delay will then be % x 0.43 1*+% x 1.05 *r= O.74 Tat its worst case! This is a lot closer to the nominal value of 0.69 1: The foregoing should make it clear why the circuit of figure 4 gives such consistently reproducible results. However, for really satisfactory operation, CMOS inverters must be used. The reason is that these gates have a threshold value of about half the supply voltage. Further, their output will always be either zero or the supply voltage. Schmitt triggers should not be used! If the delay times using 4000 series CMOS are found to be too long the new 74HCXX series can be used. These are pin and function compatible to the 74LSXX series and just as fast!