HOME     STORE     BLOG     SCHEMATICS     TUTORIALS     DOWNLOADS     CONTACT
  Electronic Schematics
FM Transmitters
PLL Synthesizers
Stereo Encoders and Decoders
Antennas
FM Receivers
Audio / Amplifiers
Power Supplies
AC/DC Inverters AC/DC Converters
Battery Chargers
Remote Control
PC Related
Test and Measurement
PIC / ATMEL / AVR
USB Circuits
Telephone Related
LED
Miscellaneous Circuits
Stepper Motors
 Schematics  >> 

Page 2 of 4:  1 2 3  4

Li-ion Battery Charger
This is a simple to build charger for single 3.7V lipo battery. The heart of the charger is TL431 shunt regulator that controls the incoming current. Charger comes with a convenient charging LED indicator. As charging current goes down so does the intensity of the LED.


Li-Po Charger and Balancer
This is a Li-Po charger and balancer project for R/C hobby.The charger circuit is based on the circuit of Electron head and all folks in the DIY electronics topic on the rcgroups.com.


LiPo Battery Charger
This is LiPo battery charger circuit based around the MAX1551 / MAX1555 chip from Maxim ICs. And it happens to be a very easy chip to use. I used the typical circuit from the datasheet and referred to the pin out to see which pin is what. I also used adapter board so that I could prototype the LiPo battery charger on a breadboard. The barrel plug towards the top goes into an LM7805 that can take 7-16V and regulates it down to 5V. Besides that, pretty simply stuff with only a handful of common components.


LIPO Battery Overvoltage Protection
Simple LIPO saver board to throw onto lithium based batteries for overvoltage protection. It consists of a TLV3012 comparator with onboard reference, an voltage divider, load resistors, indicator LED and a transistor. It should turn on the transistor, and load LIPO battery cell when its voltage is >4.25V Ive attached LIPO saver schematic. The diode represents the onboard reference in the comparator, eagle didn't have the device in its library.


LIPO Saver
The presented battery saver or TL431 LiPo Saver is designed to prevent deep discharge of lithium polymer batteries. Decreases the cell voltage of a LiPo batteries below 2.4 volts will permanently damage the cell. When LIPO battery is about to reach the critical voltage a buzzer alarm is activated. I have built several of these for use as Tx alarm and they do SCREAM especially if you fit twin piezo sounders. TL431 is adjusted to sound off at pretty much any low voltage level you wish.


LiPoly charging with MCP73833
For my latest projects I used a lot of single cell lipo batteries. They are really nice. High power density, low self-discharge, no memory effect and they can deliver quite an amount of current. But lipo battery handling is a bit more complicated as with other rechargeable batteries. You have to take care of under voltage and over charging as that may destroy the battery.


Lipoly Low Battery Indicator
Lipoly batteries are great power source for our AEGs, they offer high current capacities and are available in different shapes and sizes that can fit virtually any AEG. But they have a downside, they are prone to failures when over discharged. Their nominal voltage is 3.7V (4.2V-full charge) but must not go below their critical voltage of 2.7V. New development in AEG electronics protect the battery from going too low by either cutting the power or an audible warning that indicates low battery voltage. While saving up for the "Panther" or "Cheetah" SW-COMP, here is a cheap and easy to construct 11.1V lipoly lo-batt indicator.


Lithium Ion / Lithium Polymer USB Battery Charger
This is a MAX1811 based USB charger that can handle both Lithium Ion and Lithium Polymer 3.7V battery. It requires very few external components and provides ability to select between 4.1v and 4.2v battery regulation for different types of LiPo batteries. You can select between either 100mA and 500mA current charging mode and LED provides the status of the charging.


Lithium Ion Battery Charger with Microchip MCP73831
Here's a simple and inexpensive compact lithium ion / polymer battery charger based on Microchip's MCP73831 IC. It features adjustable current charging from 15mA up to 500mA for single cell lipo batteries. With this lipo charger just a few external components are needed. Constant voltage power supply of 5 ~ 6V is needed. Power can also be drawn from USB port. When USB power is 150mA charge current should not be higher. Charge current can be adjusted with external resistors. External LED provides status when lipo battery is fully charged. The LED lights when battery is fully charged. The maximum charging voltage is selectable from 4.2 to 4.5. This has to be chosen at the time of purchase. Typically 4.2V is a standard charging voltage. MCP73831-2 <- 4.2V, MCP73831-3 <- 4.3V, MCP73831-4 <- 4.4V, MCP73831-5 <- 4.5V.


Lithium Ion, Lithium Poly Charger Circuit
The above circuit will charge any 2-cell * Li-Ion battery pack. Maximum current is about 650 milliamps. The circuit is designed for batteries of 900mah or higher. Note this circuit is NOT for Li-Metal batts (i.e. Duralites). Power source can be a 12v Gell cell (Power panel), or can be powered by a car's cigarette lighter. I use an old 12v DC wall transformer (800ma or more.) Radio shack sells a 12v/1amp wall DC adapter #273-1776 that will work. Supply does not need to be regulated. In fact my cheap supply outputs 17 volts with no load.


Page 2 of 4:  1 2 3  4


Accurate LC Meter Capacitance Inductance Meter with 16F628 and LCD
Volt Ampere Meter with 16F876 Microcontroller and LCD display
 
Accurate LC Meter

Build your own Accurate LC Meter (Capacitance Inductance Meter) and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils and inductors. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging as well as reset switch and produces very accurate and stable readings.
PIC Volt Ampere Meter

Volt Ampere Meter measures voltage of 0-70V or 0-500V with 100mV resolution and current consumption 0-10A or more with 10mA resolution. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored. The meter uses PIC16F876A microcontroller with 16x2 backlighted LCD.

50MHz 60MHz Frequency Meter / Counter with 16F628 & LCD
1Hz - 2MHz XR2206 Function Generator
60MHz Frequency Meter / Counter

Frequency Meter / Counter measures frequency from 10Hz to 60MHz with 10Hz resolution. It is a very useful bench test equipment for testing and finding out the frequency of various devices with unknown frequency such as oscillators, radio receivers, transmitters, function generators, crystals, etc.
1Hz - 2MHz XR2206 Function Generator

1Hz - 2MHz XR2206 Function Generator produces high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated. Output of 1Hz - 2MHz XR2206 Function Generator can be connected directly to 60MHz Counter for setting precise frequency output.

BA1404 HI-FI Stereo FM Transmitter
USB IO Board PIC18F2455 / PIC18F2550
BA1404 HI-FI Stereo FM Transmitter

Be "On Air" with your own radio station! BA1404 HI-FI Stereo FM Transmitter broadcasts high quality stereo signal in 88MHz - 108MHz FM band. It can be connected to any type of stereo audio source such as iPod, Computer, Laptop, CD Player, Walkman, Television, Satellite Receiver, Tape Deck or other stereo system to transmit stereo sound with excellent clarity throughout your home, office, yard or camp ground.
USB IO Board

USB IO Board is a tiny spectacular little development board / parallel port replacement featuring PIC18F2455/PIC18F2550 microcontroller. USB IO Board is compatible with Windows / Mac OSX / Linux computers. When attached to Windows IO board will show up as RS232 COM port. You can control 16 individual microcontroller I/O pins by sending simple serial commands. USB IO Board is self-powered by USB port and can provide up to 500mA for electronic projects. USB IO Board is breadboard compatible.

ESR Meter / Transistor Tester Kit
Audiophile Headphone Amplifier Kit
 
ESR Meter / Capacitance / Inductance / Transistor Tester Kit

ESR Meter kit is an amazing multimeter that measures ESR values, capacitance (100pF - 20,000uF), inductance, resistance (0.1 Ohm - 20 MOhm), tests many different types of transistors such as NPN, PNP, FETs, MOSFETs, Thyristors, SCRs, Triacs and many types of diodes. It also analyzes transistor's characteristics such as voltage and gain. It is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors. Unlike other ESR Meters that only measure ESR value this one measures capacitor's ESR value as well as its capacitance all at the same time.
Audiophile Headphone Amplifier Kit

Audiophile headphone amplifier kit includes high quality audio grade components such as Burr Brown OPA2134 opamp, ALPS volume control potentiometer, Ti TLE2426 rail splitter, Ultra-Low ESR 220uF/25V Panasonic FM filtering capacitors, High quality WIMA input and decoupling capacitors and Vishay Dale resistors. 8-DIP machined IC socket allows to swap OPA2134 with many other dual opamp chips such as OPA2132, OPA2227, OPA2228, dual OPA132, OPA627, etc. Headphone amplifier is small enough to fit in Altoids tin box, and thanks to low power consumption may be supplied from a single 9V battery.
 

Arduino Prototype Kit
RF Remote Control 433MHz Four Channel
 
Arduino Prototype Kit

Arduino Prototype is a spectacular development board fully compatible with Arduino Pro. It's breadboard compatible so it can be plugged into a breadboard for quick prototyping, and it has VCC & GND power pins available on both sides of PCB. It's small, power efficient, yet customizable through onboard 2 x 7 perfboard that can be used for connecting various sensors and connectors. Arduino Prototype uses all standard through-hole components for easy construction, two of which are hidden underneath IC socket. Board features 28-PIN DIP IC socket, user replaceable ATmega328 microcontroller flashed with Arduino bootloader, 16MHz crystal resonator and a reset switch. It has 14 digital input/output pins (0-13) of which 6 can be used as PWM outputs and 6 analog inputs (A0-A5). Arduino sketches are uploaded through any USB-Serial adapter connected to 6-PIN ICSP female header. Board is supplied by 2-5V voltage and may be powered by a battery such as Lithium Ion cell, two AA cells, external power supply or USB power adapter.
200m 4-Channel 433MHz Wireless RF Remote Control

Having the ability to control various appliances inside or outside of your house wirelessly is a huge convenience, and can make your life much easier and fun. RF remote control provides long range of up to 200m / 650ft and can find many uses for controlling different devices, and it works even through the walls. You can control lights, fans, AC system, computer, printer, amplifier, robots, garage door, security systems, motor-driven curtains, motorized window blinds, door locks, sprinklers, motorized projection screens and anything else you can think of.
 
  Latest Schematics
FM Transmitter with Booster
TDA7000 FM Radio Receiver with LM386 Amplifier
BA1404 Stereo FM Transmitter with Booster
Portable Variable Bench Power Supply 1-32V 0-5A
1 Watt FM Transmitter Booster
Arduino DCC Decoder
Simplest FM Receiver
7W FM Transmitter
Simple Stereo FM Transmitter using an AVR Microcontroller
Stereo FM Receiver
Simple DIY FM Transmitter
50W Power Amplifier with LM3886
BLF147 150W VHF Amplifier
Fully Adjustable Power Supply
Stereo FM Transmitter with BA1404 IC
High Performance Stereo Audio Amplifier using LM3886
1Km FM Transmitter with UA741 Opamp
Easy Crystal Locked FM Transmitter
Adjustable Delay Circuit
DIY Adjustable Bench Power Supply
BA1404 FM Stereo Transmitter with Amplifier
LM350 3A Adjustable Voltage Regulator
1 Watt FM Amplifier
TDA2050 Stereo Audio Power Amplifier
DIY Walkie Talkie
5km FM Transmitter
Bench Lab Power Supply 0-50V 0-5A
Tiny FM Transmitter
3V One Transistor FM Transmitter
FM Music Transmitter

Electronics-DIY.com © 2002-2024. All Rights Reserved.