Electronic schematics, circuits and kits http://electronics-diy.com Sat, 21 Dec 2024 06:42:19 -0500 http://electronics-diy.com en http://electronics-diy.com/electronic_schematic.php?id=1396 http://electronics-diy.com/electronic_schematic.php?id=1396
This little 88-108MHz FM transmitter has a range of up to 1 mile in the open. The transmitter consists of three stages. The first stage is an audio pre-amplifier built around 2SC9014 transistor, second stage is an oscillator built using 2SC9018 transistor, and third stage is an RF amplifier built around 2SC9018 transistor. RF amplifier stage increases an output power, range and stability by separating the antenna from the oscillator. ]]> http://electronics-diy.com/electronic_schematic.php?id=1394 http://electronics-diy.com/electronic_schematic.php?id=1394
Simple circuit and easy to assemble DIY TDA7000 FM radio receiver with LM386 amplifier chip. Assembling an FM radio is always something interesting to the electronics enthusiast. TDA7000 which integrates a mono FM radio all the way from the aerial input to the audio output. Outside of the TDA7000 IC there is only one tunable LC circuit for the local oscillator, a few inexpensive ceramic capacitors and one resistor. The TDA7000 dramatically reduces assembly and post production alignment costs because only the oscillator circuit needs adjustment during manufacture to set the limits of the tuned frequency band. The complete FM radio can be made small enough to fit inside a calculator, cigarette lighter, key-ring fob or even a slim watch. The TDA7000 can also be used as receiver in equipment such as cordless telephones, CB radios, radio-controlled models, paging systems, the sound channel of a TV set or other FM demodulating systems.]]> http://electronics-diy.com/electronic_schematic.php?id=1393 http://electronics-diy.com/electronic_schematic.php?id=1393
Build your own fairly simple high quality stereo FM transmitter circuit as shown in the photo. The circuit is based on the BA1404 chip from ROHM Semiconductors and S9018 amplifier for extending tansmitter's range. BA1404 is a monolithic FM stereo modulator that has built in stereo modulator, FM modulator, RF amplifier circuits. The FM modulator can be operated from 76 to 108MHz and the power supply for the circuit can be anything between 6 to 12 volts.]]> http://electronics-diy.com/electronic_schematic.php?id=1392 http://electronics-diy.com/electronic_schematic.php?id=1392
I have gone without a variable lab bench power supply for too long now. The power supply that I have been using to power most of my projects has been shorted out too many times. I have actually killed 2 by accident and needed a replacement. I had many 18650 lipo batteries lying around my workshop so I decided to use them to build a portable variable bench power supply that could be easily moved around and used on the go. The power supply consists of DC-DC step up power module, voltage and current display, a switch, standard size 10K trim pots, XT-60 and a balance connector for charging an array of 8x4 18650 batteries.]]> http://electronics-diy.com/electronic_schematic.php?id=1391 http://electronics-diy.com/electronic_schematic.php?id=1391
1 Watt FM Transmitter amplifier with a reasonably balanced design specified to boost a RF frequency in the 88 – 108 MHz spectrum. It may be considered a fairly sensitive configuration when used with quality RF power amplifier transistors, trimmers and inductors. It involves a power amplification factor of 9 to 12 dB (9 to 15 times). At an input power of 0.1W the output may be well over 1W. It's advisable to choose T1 transistor on the basis of the input voltage. For 12V voltage it is recommended to use transistors such as 2N4427, KT920A, KT934A, KT904, BLX65, 2SC1970, BLY87. For 18-24V voltage may may want to use transistors such as 2N3866, 2N3553, KT922A, BLY91, BLX92A. You may also consider using 2N2219 with 12V input voltage however that would only produce an output power of around 0.4W. ]]> http://electronics-diy.com/electronic_schematic.php?id=1390 http://electronics-diy.com/electronic_schematic.php?id=1390
Modern model railroads are digitally controlled using a Digital Command Control (DCC) protocol similar to network packets. These data packets contain device address and instruction set that is embedded in the form of AC voltage and fed to train track to control locomotives. The great advantage of DCC over analog DC control is that you can independently control the speed and direction of many locomotives on the same train track as well as control many other lights and accessories using that same signal and voltage. Commercial DCC decoders are available on the market however their cost can add up pretty quickly if you have a lot of devices to control. Luckily you can build a simple Arduino DCC decoder yourself to decode DCC signal and control up to 17 LEDs / accessories per each DCC decoder.]]> http://electronics-diy.com/electronic_schematic.php?id=1389 http://electronics-diy.com/electronic_schematic.php?id=1389
This is perhaps one of the simplest and smallest FM receivers for receiving local FM stations. It's simple design makes it ideal for a pocket sized FM receiver. The audio output of the receiver is amplified through LM386 amplifier chip that can drive a small speaker or headphones. The circuit is powered by three AAA or AA battery cells. FM receiver section uses two RF transistors for converting frequency modulated signals to audio. L1 coil and 22pF variable capacitor form a tuned tank circuit that is used for tuning to any available FM stations.]]> http://electronics-diy.com/electronic_schematic.php?id=1388 http://electronics-diy.com/electronic_schematic.php?id=1388
This a build of a well known FM transmitter called Veronica. Transmitter was built on two separate boards. The first board (pictured above) is the Veronica transmitter itself with output power of 600mW when powered by 12V voltage or 1W when powered by 16V voltage. The second board is an RF power amplifier that uses 2SC1971 transistor to amplify Veronica's output signal to around 7 Watts. Although transmitter can be powered with 9-16V voltage, it is recommended that both transmitter and amplifier is powered by 12V voltage as 600mW is an upper limit for driving 2SC1971 transistor.]]> http://electronics-diy.com/electronic_schematic.php?id=1387 http://electronics-diy.com/electronic_schematic.php?id=1387
I had been fascinated with the idea of making simple stereo encoder for building Stereo FM Transmitter. Not that stereo means much to me away from the computer. I use an FM broadcast transmitter to relay the output of my computers to FM radios in the kitchen, the bedroom, the driveway, and out in the garden. Under those circumstances, I find that mono is plenty, whether it is music or radio programs from over the internet, since I am primarily occupied with something else anyway. When on my hands and knees in the garden, all the way up to my elbows in planting a bush, the music really does not seem any more sweet when its stereo. But that did not stop me from being fascinated with the idea of making a stereo encoder. Stereo always seemed like a lot of circuitry and bother for the slight benefit that came with it. That is, until a few weeks ago.]]> http://electronics-diy.com/electronic_schematic.php?id=1386 http://electronics-diy.com/electronic_schematic.php?id=1386
High sensitivity TEA5711 receiver allows the reception of distant stations from over 150 miles (240 km) away. Good selectivity is obtained with narrow bandwidth ceramic filters. AFC automatic frequency control locks on stations for drift-free reception. Stereo separation which depends on signal strength is very apparent on strong signals. And with high quality headphones, the sound is rich with deep base and high treble, for hours of enjoyable stereo music.]]> http://electronics-diy.com/electronic_schematic.php?id=1385 http://electronics-diy.com/electronic_schematic.php?id=1385
Ever wondered how come you can just simply tune in to your favorite FM Radio Channel. Moreover, ever had the curiosity of making your own FM Station on a specific frequency? Well if the answer is Yes to any of those questions then you are at the right place!. We are going to look into making small FM Transmitter for Hobby Purposes with a really basic component guide and components that are readily available off the shelf. ]]> http://electronics-diy.com/electronic_schematic.php?id=1384 http://electronics-diy.com/electronic_schematic.php?id=1384
This is my second encounter with LM3886. I was pleased with the sound this chip produced the first time, so I decided to make another amplifier with it. The schematic is based on the schematic in the datasheet of the chip with minor changes. I removed the time delay capacitor connected to MUTE pin, because it’s better to use separate DC protection schematic which has similar functionality. I made the output inductance L1 by winding 15 turns of enameled wire around the resistor R7. The diameter of the wire must be minimum 0.4mm. The whole was wrapped with heat shrink. I used 47uF/63V non polarized capacitor for C2. It can be regular electrolytic capacitor, but it’s better to use non-polarized or bipolar. ]]> http://electronics-diy.com/electronic_schematic.php?id=1383 http://electronics-diy.com/electronic_schematic.php?id=1383
One of the very latest developments here is 150W VHF transmitter amplifier with BLF147 power transistor. Results are very impressive with well over 150W across the band with 10W input and 24 VDC supply. Over 200W is achieved at 28 VDC, and over 250W with a hot bias 4-5A quiescent. PCB is teflon glass board with printed transmission lines and porcelain caps. No external harmonic filter is needed, as the filtering is built into the matching network.]]> http://electronics-diy.com/electronic_schematic.php?id=1382 http://electronics-diy.com/electronic_schematic.php?id=1382
This circuit uses an LM317 regulator, chosen because of its built-in over-current and over-temperature protection. Its output is boosted up to 5A by the MJ2955 transistor. The output voltage is varied by adjusting VR1 potentiometer. Adjustable current limiting from 60mA to 5A is provided by op amp TL071 IC that is used as a comparator which monitors the voltage across the 0.1 Ohm current sensing resistors.]]> http://electronics-diy.com/electronic_schematic.php?id=1381 http://electronics-diy.com/electronic_schematic.php?id=1381
There are many applications for an FM transmitter, particularly if it can broadcast in stereo. You can broadcast stereo signals from your CD player or any other source to an FM tuner or radio. This FM Transmitter uses a single BA1404 IC and a few other components. It broadcasts on the 88-108MHz FM band so that it can be received by any standard FM tuner or portable radio. Transmitter runs from a 5V supply and can drive a dipole antenna for improved range.]]> http://electronics-diy.com/electronic_schematic.php?id=1380 http://electronics-diy.com/electronic_schematic.php?id=1380
The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4? load and 38W into 8? with 0.1% THD+N from 20Hz–20kHz. The performance of the LM3886, utilizing its Self Peak Instantaneous Temperature SPiKe protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area. SPiKe protection means that these parts are completely safeguarded at the output against over voltage, under voltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks. The LM3886 maintains an excellent signal-to-noise ratio of greater than 92dB. It exhibits extremely low THD+N values of 0.03% at the rated output into the rated load over the audio spectrum, and provides excellent linearity with an IMD typical rating of 0.004%.]]> http://electronics-diy.com/electronic_schematic.php?id=1379 http://electronics-diy.com/electronic_schematic.php?id=1379
This project is the construction of FM transmitter circuit for commercial radio frequencies between 88 MHz and 108 MHz. The transmitter is easy to build and offers good frequency stability through the usage of UA741 oamp. 1Km range can be achieved when powered by 9V battery with 30cm long telescopic antenna. ]]> http://electronics-diy.com/electronic_schematic.php?id=1378 http://electronics-diy.com/electronic_schematic.php?id=1378
The circuit presented here uses a crystal oscillator and frequency multiplier to generate a highly-stable carrier signal frequency of 96MHz. It can be used to transmit voice or music up to hundred meters. The circuit is built around 9018 transistor, 24MHz crystal, air coil and a few other basic components.]]> http://electronics-diy.com/electronic_schematic.php?id=1377 http://electronics-diy.com/electronic_schematic.php?id=1377
Build an adjustable auto power On Off delay timer circuit using CD4541 timer. This electronic timer circuit is helpful when you need to power On/Off any AC Appliances after a pre-defined duration. Delay time it can be adjusted from about 2 to 120 seconds.]]> http://electronics-diy.com/electronic_schematic.php?id=1376 http://electronics-diy.com/electronic_schematic.php?id=1376
Every electronics hobbyist needs at least one bench power supply in his house for tinkering with some weekend projects. This small power supply was built with an old 19V 3A laptop charger and buck-boost converter. Output voltage is continuously adjustable from 1.25V to 33V with up to 3A current. I have been using it for 3 weeks now and have realized that I am using it more than I thought I would.]]>