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If you need to use a headset with your PC, then you will know how frustrating it is continuously swapping over speaker and microphone cables. This is even worse if the PC is parked in a dark corner and the hard-to-read writing on the sound card sockets is covered in dust. This simple switch box eliminates all these problems. It sits on top of the desk and connects to the PC with stereo one-to-one cables. On the rear of the box are sockets for the PC speaker and microphone connections and the existing speakers. On the front of the box are the sockets for the headset microphone and headphones, an input for an external microphone and two switches. One switch is used to direct the sound card output from the PC to either the existing speakers or the headphones. Circuit diagram: Speaker-Headphone Switch Circuit Diagram For Computers The second switch connects either the headset microphone or the external microphone to the input socket of the PC sound card. The switches used were 3 position 4...

Inductorless 3-to-5 Volts Converter Circuit Diagram. By configuring a comparator and a transistor to control the oscillator in a charge pump circuit, you enable the pump to generate a regulated output of in principle any desired value. Charge pump ICs can either invert or double an input voltage (for example, 3 V to –3 V or 3 V to 6 V). The charge pump itself does not regulate the output voltage and one running off 3 V is not normally capable of generating intermediate output voltage levels like 5 V. However, by adding a comparator and a reference device, you can create arbitrary output levels like 5 V and regulate them as well. Inductorless 3-to-5 Volts Converter Circuit Diagram Charge pump IC1 (a MAX660) has an internal oscillator whose 45 kHz operation transfers charge from C1 to C2, causing the regulated output to rise. When the feedback voltage (pin 3 of IC2) exceeds 1.18 V, the output of comparator IC2 (a MAX921) goes high, turning off the oscillator via T1. The comparator hyste...

An ELT (Emergency Locator Transmitter, also known as a distress beacon) is an emergency radio transmitter that is activated either manually or automatically by a crash sensor to aid the detection and location of aircraft in distress. This acoustic ELT project is intended for radio control (RC) model aircraft, which every now and then decide to go their own way and disappear into the undergrowth. Circuit diagram : Acoustic Distress Beacon Circuit Diagram The audio locating device described here enables model aircraft that have landed ‘off limits’ to be found again and employs its own independent power supply. The small cam-era battery shown in the circuit activates an acoustic sounder when radio contact is lost and produces a short signal tone (bleep) every ten seconds for more than 25 hours. Current consumption in standby and passive (with jumper J1 set) modes is negligible. The timing generator for the alarm tone is the Schmitt trigger AND-gate IC1.B; its asymmetric duty cycle drive...

LIGHT ALARM - 1 This circuit operates when lightweight|the sunshine} Dependent Resistor receives light. When no lightweight falls on the LDR, its resistance is high and also the transistor driving the speaker isn't turned on. When lightweight falls on the LDR its resistance decreases and also the collector of the second transistor falls. This turns off the primary transistor slightly via the second 100n and also the initial 100n puts a further spike into the bottom of the second transistor. This continues till the second transistor is turned on as onerous because it will go. the primary 100n is currently nearly charged and it cannot keep the second transistor turned on. The second transistor starts to turn off and each transistors swap conditions to provide the second half of the cycle. LIGHT ALARM - 2 This circuit is comparable to lightweight Alarm -1 however produces a louder output as a result of the speaker being connected directly to the circuit. The circuit is essentially a h...

In these times with viruses and other threats from the Internet it would be nice to have reassurance that the PC cannot be infected. That is why this circuit was designed. It makes it possible to install multiple hard disks inside the case of a PC, which are separated in such a way that viruses cannot move from one disk to another. In this case there are three drives installed, one for use of the Internet via ADSL, one for working with email and one for other applications. If data from the Internet never arrives on the third disk, it is effectively protected against viruses. The solution outlined here has been in satisfactory use for a couple of years. There is an additional benefit: if there are ever any problems with the operation of the computer, then it is very easy to change to another hard disk to check if the problem manifests itself there as well. In this case, fault finding can be made much easier. The circuit operates by only switching over the power supply voltages (5 V and ...

Simple Mock Alarm with Call Bell Circuit Diagram is a fully automatic mock alarm to ward off any intruder to your house. The alarm becomes active at sunset and remains ‘on’ till morning. The flashing light-emitting diodes (LEDs) and beeps from the unit simulate the functioning of a sophisticated alarm system. Besides, the circuit turns on and off a lamp regularly at an interval of 30 minutes throughout the night. It also has a call bell facility. The circuit is built around CMOS IC CD4060B (IC1), which has an internal oscillator and a 14-stage binary divider to provide a long delay without using a high-value resistor and capacitor. Press switch S2 to provide 9V power supply to the circuit. During daytime, light-dependent resistor LDR1 offers little resistance and transistor T1 conducts. This drives transistor T2 into the cut-off mode, as its base is pulled to ground via transistor T1. Reset pin 12 of IC1 remains high as long as transistor T2 is cut off. This keeps the oscillator of IC...

My blog has now just crossed 200,000 views! I am extremely happy that it’s gotten this many views and that I’ve been able to reach out to so many people from all across the world. I love writing tutorials and articles about microcontrollers, power electronics, SMPS and everything electronics! I love it even more when my writing reaches out to people from all over the world to help them learn something new or to find the solution to some problem! So, I say thank you to all my readers and followers and hope that I have been able to help you and that I can continue helping you! If you have any topic in mind that you want me to write about, please mention that in the comments. While I cannot promise you that I will write up on it, I will certainly try. University has started (if you’re wondering why the title says Ithaca, that’s because Cornell University is located in Ithaca, New York, USA) and it’s been a month. The work load is quite high, so I may take quite a while to write some new ...

Whenever a current is flowing, the current will meet some resistance or something will impede its flow, the amount of voltage loss through the entirety of a circuit, or even a part is voltage drop. In low voltage lighting systems such as flexible LED strip lights, voltage drops occur because the input voltage from the power supply gradually decreases over the length of the strip. The longer the flexible led strip light tape, the more resistance the current has to overcome, hence it loses voltage along the way. The result is dimming lights the further down the LED strip you get because the light emitting diodes (SMD chips) at the end of the strip are less bright than those at the start, which is closest to the power supply. This condition causes the load to work harder with less voltage pushing the current. If the flexible LED strip light runs off a 12-volt power supply, then you have 12 volts going into the strip light system at the start but the other end will not have 12 volts due to...

Most 3-terminal active components can be  tested statically using just an ohmmeter. But  when you have a lot of these devices to test,  the procedure soon becomes boring. That’s  where the idea came from to combine fast,  easy testing for these types of device into a  single instrument. The unit described here enables you to test  NPN and PNP bipolar transistors, N-or Pchannel FETs or MOSFETs, UJTs, triacs, and thyristors. Regardless of the type of device, the  tests are non-destructive. Universal connectors allow testing of all package types, including SMDs (up to a point). The unit lets you  change from one type of device to another in  a trice. It avoids using a multi-pole switch, as  they’re too expensive and hard to find. Circuit diagram : Universal Tester for 3-pin Devices Circuit Diagram Here’s how to build a versatile instrument at  a ridiculously low cost. IC1 is a 4066 quad CMOS switch which will let us switch between bipolar transistors and FETs. LEDs D1–D4 tell us abou...

This circuit was designed to assist the installation of TV antennas. The signal is monitored using a small portable TV set and this circuit monitors the output of the TV's FM detector IC via a shielded lead. To initially calibrate the meter, adjust trimpot VR2 to zero the meter. Trimpot VR1 is a sensitivity control and can be set for a preset reading (ie, 0dB) or can be calibrated in millivolts. Rotating the antenna for a minimum reading on the meter (indicating FM quieting) gives the optimum orientation for the antenna. Circuit diagram: TV Relative Signal Strength Meter Circuit Diagram

This circuit uses a 555 timer as the bases of the touch switch. You can learn more about 555 timers in the Learning section on my site. When the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10M resistor on pin 2 causes the the circuit to be very sensitive to the touch.

Normally, Theremin works by detecting hand proximity using capacitive coupling method. A Theremin circuit shown in the schematic diagram below use different method to control the pitch. The oscillator of this tone generator, both the volume and frequency  are controlled using LDRs, a light sensitive electronic component, so we can call this circuit an optical Theremin .  Look at the following schematic diagram.  Simple Optical Theremin Circuit Diagram LDR1 control the frequency of this Theremin, while LDR2 control the volume level. We can place the LDR in two boxes where we can use our hand to control the aperture of the box, allowing smooth control of light amount that expose the LDR.  This light is expected to come from ambient light, entering the box through the hand controlled aperture. This optical Theremin assume a stable ambient light to produce smooth control. The output will be heard on a small loudspeaker, but will be in very low volume. You can just amplif...

General Description: The TDA 2003 hasimproved performancewith the  same pin configuration as the TDA 2002.  The additional features of TDA 2002, very low  numberof externalcomponents,ease of assembly,  space and cost saving, are maintained.  Thedeviceprovidesa high outputcurrentcapability  (up to 3.5A) very low harmonic and cross-over  distortion.  Completely safe operation is guaranteed due to  protectionagainst DCand ACshort circuit between  all pins and ground,thermal over-range,load dump  voltage surge up to 40V and fortuitous open  ground. Circuit Diagram: Circuit diagram for 10 Watt car radio audio amplifier Datasheet for TDA2003:  Download

Actually you can not bother to design a multiplexer using logic gates because it has many special IC which functioned for a multiplexer. One of the TTL ICs from the family that you can use to fulfill the function of a multiplexer is IC 74 251. At the IC there are 8 input channels and 3-bit selector and the other lane as a control reset and inverting output. As a note if you are using TTL ICs for your electronic circuit, the voltage supply that is allowed a maximum of 5 volts. So you can be more familiar with the workings of this multiplexer ic, IC74251 consider the truth table below: C B A G Y W X X X 1 Z Z 0 0 0 0 D0 D0’ 0 0 1 0 D1 D1’ 0 1 0 0 D2 D2’ 0 1 1 0 D3 D3’ 1 0 0 0 D4 D4’ 1 0 1 0 D5 D5’ 1 1 0 0 D6 D6’ 1 1 1 0 D7 D7’ Z = High impedance (off) D0,D1…D7 = Representing the output of the input lines D

Now you'll be able to perpetually grasp the precise time. With this style you'll be able to have an atomic clock in your area. Isn’t that great? scan on to grasp additional. First of all, it's not regarding any radioactive components here. this can be regarding building a clock show that may get the time from the DCFF77 facilities in Frankfurt, Germany.All that's required may be a clock LED show, DCFF77 receiver, and a microcontroller at the side of the mandatory connections. Basically, the project permits a sign that's sent by the DCFF77 radio station to be decoded. After that. the microcontroller method it and sends it to the LED show to indicate the precise time. there's no got to build a sign receiver, an honest quality receiver may be bought on the net for a coffee worth. Once everything has been set within the affiliation board the PIC supply code ought to be developed. The orientation of the antenna ought to be perpendicular to Frankfurt. it'll receiv...