Wiring Schematic Diagram Guide

Simple Crystal Tester Circuit Diagram. Most electronics project working with high frequency utilizes crystal in order to generate frequency as oscillator. It is used instead of coil. Coil can be checked with multi-meter if there is any fault, but checking of crystal completely is difficult. In order to solve this problem a simple project using few components is designed call crystal tester.

This circuit consist two NPN transistors, two diode with few passive component. The crystal under test is combining with transistor T1 which further work as oscillator. The combination of transistor T1, crystal under test and capacitors C1 and C2 is work as colpiitt oscillator. If the testing crystal is good then it works as oscillator with transistor T1. The output of oscillator is rectified and filtered by diode D1 and capacitor C2 respectively and given to base of transistor T2. The signal given to base conduct transistor which further glow the LED connected to the collector through resistor R3. If the testing crystal is faulty then LED1 does not glow.

PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon unless stated otherwise)
R1 = 27 KΩ
R2 = 1 KΩ
R3 = 560 Ω
Capacitors
C1 = 0.001 µF
C2 = 100 pF
C3 = 0.001 µF
C4 = 0.004 µF
Semiconductors
D1, D2 = 1N4148
T1, T2 = BC550C
LED1 = Green
Miscellaneous
SW1 = push to on switch

Remote Field Strength Meter Circuit Diagram. This field strength meter consists of a tuned crystal detector producing a dc output voltage from a transmitted signal. The dc voltage is used to shift the frequency of a transmitter of 100-mW power operating at 1650 kHz. The frequency shift is proportional to the received field strength. This unit has a range of several hundred feet and is operated under FCC part 15 rules (100-mW max power into a 2-m-iong antenna between 510 and 1705 kHz).

 
In the last few years, the available range of operating systems for PCs  has increased dramatically. Various free (!) operating systems have been  added to the list, such as BeOS, OpenBSD and Linux. These systems are  also available in different colours and flavours (versions and  distributions). Windows is also no longer simply Windows, because there  are now several different versions (Windows 95, 98, ME, NT, XP, Vista  and 7). Computer users thus have a large variety of options with regard  to the operating system to be used. One problem is that not all hardware  works equally well under the various operating systems, and with regard  to software, compatibility is far from being universal. In other words,  it’s difficult to make a good choice.

Hard Disk Selector Circuit Diagram

Switching from one operating system to another - that’s a risky business, isn’t it? Although this may be a bit of an exaggeration, the safest approach is still to install two different operating systems on the same PC, so you can always easily use the ‘old’ operating system if the new one fails to meet your needs (or suit your taste). A software solution is often used for such a ‘dual system’. A program called a ‘boot manager’ can be used to allow the user to choose, during the start-up process, which hard disk will be used for starting up the computer. Unfortunately, this does not always work flawlessly, and in most cases this boot manager is replaced by the standard boot loader of the operating system when a new operating system is installed.

In many cases, the only remedy is to reinstall the software. The solution presented here does not suffer from this problem. It is a hardware solution that causes the primary and secondary hard disk drives to ‘swap places’ when the computer is started up, if so desired. From the perspective of the computer (and the software running on the computer), it appears as though these two hard disks have actually changed places. This trick is made possible by a feature of the IDE specification called ‘CableSelect’. Every IDE hard disk can be configured to use either Master/Slave or CableSelect. In the latter case, a signal on the IDE cable tells the hard disk whether it is to act as the master or slave device. For this reason, in every IDE cable one lead is interrupted between the connectors for the two disk drives, or the relevant pin is omitted from the connector.

This  causes a low level to be present on the CS pin of one of the drives and  a high level to be present on the CS pin of the other one (at the far  end of the cable). The circuit shown here is connected to the IDE bus of  the motherboard via connector K1. Most of the signals are fed directly  from K1 to the other connectors (K2 and K3). An IDE hard disk is  connected to K2, and a second one is connected to K3. When the computer  is switched on or reset, a pulse will appear on the RESET line of the  IDE interface. This pulse clocks flip-flop IC1a, and depending on the  state of switch S1, the Q output will go either high or low. The state  on the Q output is naturally always the opposite of that on the Q  output. If we assume that the switch is closed during start-up, a low  level will be present on D input of IC1a, so the Q output will be low  following the reset pulse.

This Precision full wave Rectifier Circuit Diagram  provides accurate full wave rectification. The output impedance is low for both input polarities, and the errors are small at all signal levels. Note that the output will not sink heavy current, except a small amount through the 10K resistors. Therefore, the load applied should be referenced to ground or a negative voltage. Reversal of all diode polarities will reverse the polarity of the output

Since the outputs of the amplifiers must slew through two diode drops when the input polarity changes, 741 type devices give 5% distortion at about 300 Hz.


Precision full wave Rectifier Circuit Diagram

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This is simple Simple TL496 3 to 9 volt converter Circuit Diagram. it uses the TL496 power supply controller, a coil and a electrolytic capacitor. The maximum output voltage is actually 8.6V and current is around 80mA.The input current (the current drawn from the batteries) is 405mA at the maximum output current. Without load the current consumption is 125µA and the batteries life is around 166 days.

This is a Simple Telephone In Use Indicator Circuit Diagram. With this circuit mounted in or near every phone in the house, it will allow users to know if the phone is being used and not to pick up the phone. When a phone is taken off hook, the voltage across the tip and ring terminals drops to 10 volts or less. This will cause the FET (2N4360) to turn on and also turn on the transistor (2N2222). When the transistor turns on it will allow current to flow through the LED and make it light. A blinking LED could be used to make the effect better. 

 

Build a 12V 7.2Ah SMF Battery Charger Circuit Diagram. The LM317 is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5A over an output-voltage range of 1.25 V to 37 V. It is exceptionally easy to use and requires only two external resistors, R2’ and R2” (R2= R2’+ R2”) to set the output voltage. Furthermore, both line and load regulation is better than standard fixed regulators. In addition to having higher performance than fixed regulators, this device includes on-chip current limiting thermal overload protection, and safe-operating-area protection. All overload protection remains fully functional, even if the ADJUST terminal is disconnected. By connecting a fixed resistor, R1 the ADJUST and OUTPUT terminals, the LM317 can function as a precision current regulator. An optional output capacitor can be added to improve transient response.

 

The ADJUST terminal can be bypassed to achieve very high ripple-rejection ratios, which are difficult to achieve with standard three-terminal regulators. A capacitor of small value should be connected across the input pin of LM317 and ground, particularly if the regulator is not in close proximity to the power-supply filter capacitor.

Please note that the output can go no lower than 1.25 Volts.The Input voltage must be about 3 Volts above the desired Output Voltage. So input voltage should be around 18V.So a transformer with the secondary voltage of 17 V is used.

Vo is calculated by following formula ,  Vo = Vref * ( 1 + R₂/R₁ )

Where Vo is the voltage drop across the output i.e voltage applied to the charge the battery.

Here  Vref = 1.25.Making R1 a standard value, like 220 Ohms sets the current through R2 as well. Now all we have to do is select the value of R2 to give us a voltage drop of our desired V OUT, minus the 1.25 Volts across R1.

So for Vo_maximum=15 v and Vo_minimum=12 v we get respective values of R_2minimum=1K8  and  R_2maximum=2K3 which we will get by keeping R₂’=1k8  and R₂”=500 Ohms (variable).

The most commonly used OPAMPS are 741 and 324. IC741 is used in close loop configuration and LM324 in open loop configuration. i.e. LM324 mainly used as comparator while 741 for amplification,addition etc

LM317 regulates the Output at 1.25 Volts above the Reference pin. Knowing this the value of this resistor sets the current through both resistors. The current drawn by the Reference pin is small and can be ignored as long as the current through the resistors is around 1 mA to 10 mA.

Output voltage can be varied and obtained as wanted(between 12v and 15v,minimum and maximum charging voltages. Observed voltage values at INPUT ,OUTPUT and ADJUST pins is shown in table.While testing take enough precaution as not to short OUTPUT and ADJUST pins as it may damage the transistor BC 547,whose collector is connected to adjustment pin.

The difference between voltage at output pin and adjustment pin is 1.23 (~1.25) which is the reference voltage Vref. Current rating of battery to be charged 7.2 Ah 12v, short circuit current Isc = 720mA .Using multi-meter check the short circuit current.If the Isc shows a different value than expected,it can be changed by increasing or decreasing the load connected between the emitter of the transistor T1 and ground.

The circuit uses two LEDs as indicators; one for signaling charging ON condition,and the other as an indicator , when charging voltage falls below  its terminal voltage (~12 volts). Terminal voltage can be adjusted by adjusting the 1k Trimpot. The output voltage range can be adjusted by 500 ohm Trimpot. LM324 is used in comparator circuit,after the rectifier circuit. Comparator will compare the voltage levels,and if the output voltage is less than the charging voltage,the voltage across the red LED will go high thus indicating drop in charging voltage.

If the battery is connected to the charger but unplugged from the power source, you end up with the input voltage of the circuit disconnected while the output voltage is still present. Some regulators can be damaged by this, and thus diodes are put into the circuit to protect them.

SMF batteries or VRLA batteries (valve-regulated lead-acid battery) are made in an eco-friendly, ISO Certified & modern plant with a large manufacturing capacity and are being sold worldwide. There is a wide range available to suit all applications of standby power requirement’s, for example:

etc. come in factory charged conditions and have a high shelf life thereby requiring longer time intervals between recharging of batteries in stock.  Source : Link

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.

Build a simple audio Milli volt meter circuit diagram. This Audio Milli Volt Meter Circuit has a flat response from 8Hz to 50 kHz at -3 db on tbe 10-mV range. The upper limit remains the same on tbe less sensitive ranges, but the lower frequency limit covers under 1 Hz.

How to build a Crystal-controlled-reflection-oscillator circuit diagram . This is a simple crystal controlled reflection oscillator circuit, this unit is easily tunable and stable, consumes little power, and costs less than other types of oscillators tlmt operate at the same frequencies. This unusual combination of features is made possible by a design concept that includes operation of the transistor well beyond the 3 dB frequency of its current-versus- frequency curve. 

The concept takes advantage of newly available crystals that resonate at frequencies up to about 1 GHz.The emitter of transistor Q is connected with variable capacitor Cl and series-resonant crystal X. The emitter is also connected to ground through bias resistor Rl. The base is connected to the parallel combination of inductor L and capacitor C3 through DE-blocking capacitor and C4 and is forward biased with respect to the emitter by resistors R3 and R4. 

Impedance Z could be the 220-0 resistor shown or any small impedance that enables the extraction of the output signal through coupling capacitor C2. If Z is a tuned circuit, it is tuned to the frequency of the crystal. 

 

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This is a simple audio Milli volt meter circuit diagram. This Audio Milli Volt Meter Circuit has a flat response from 8Hz to 50 kHz at -3 db on tbe 10-mV range. The upper limit remains the same on tbe less sensitive ranges, but the lower frequency limit covers under 1 Hz.