Mini variable power supply
https://www.electronics-lab.com/project/mini-variable-power-supply/
Description T1 steps down AC voltage from 115VAC (or 220VAC) to about 8VAC and is then rectified via bridge rectifier BR1 to about 11.52Vdc. C1 filters off the AC ripple. If you find the circuit output too noisy add another electrolytic capacitor over the output terminals. Value can be between 10 and 100uF/25V. The output […]
Charger for mobile phones
https://www.electronics-lab.com/project/charger-for-mobile-phones/
Description Most mobile chargers do not have current/voltage reguLation or short-circuit protection. These chargers provide raw 6-12V DC for charging the battery pack. Most of the mobile phone battery packs have a rating of 3.6V, 650 mAh. For increasing the life of the battery, slow charging at low current is advisable. Six to ten hours […]
Li-Ion Charger
https://www.electronics-lab.com/project/li-ion-charger/
Description The LP2951 regulator is manufactured by National Semiconductors. The choice of values is from an application note “Battery Charging”, written by Chester Simpson. Diode D1 can be any diode from the 1N00x series, whichever is conveniently available. It functions as a blocking diode, to prevent a back flow of current from the battery into […]
Lead Acid Battery Charger #2
https://www.electronics-lab.com/project/lead-acid-battery-charger-2/
Description The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage. The output voltage is: 1.2 x (P1+R2+R3)/R3 volt. Current limiting kicks in when the current is about […]
Lead Acid Battery Charger #1
https://www.electronics-lab.com/project/lead-acid-battery-charger-1/
Description Except for use as a normal Battery Charger, this circuit is perfect to ‘constant-charge’ a 12-Volt Lead-Acid Battery, like the one in your flight box, and keep it in optimum charged condition. This circuit is not recommended for GEL-TYPE batteries since it draws to much current. The above circuit is a precision voltage source, […]
Simple 78xx Current Booster
https://www.electronics-lab.com/project/simple-78xx-current-booster/
Description Voltage regulators such as the LM78xx, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be used (See the project on the 3-part […]
1.2v LED Flasher – Joule thief
https://www.electronics-lab.com/project/1-2v-led-flasher-joule-thief/
This is a 1.2-volt single transistor flyback (Joule Thief) circuit that features a third coil. With it, flash duration and brightness is much enhanced, even with just a 10uF capacitor, as can be seen in the schematic. Description The parts to the right of T1 form a simple Joule-thief (‘Blocking’ oscillator) circuit which boosts the […]
13.8V/40A Stabilized Power Supply
https://www.electronics-lab.com/project/13-8v40a-stabilized-power-supply/
This power supply was designed for ham-radio use and has been in operation for over 10 years. Its design is very simple and practically immune to RF. It is assembled from discrete components, being the most costly element a 600VA toroidal transformer, which can be replaced by another with different characteristics, provided it has a […]
Dual Voltage Power Supply
https://www.electronics-lab.com/project/dual-voltage-power-supply/
Description The following circuit Diagram of (DUAL VOLTAGE POWER SUPPLY ) can be used for Misc.. application. It requires a few components to built. The most important components of this circuit are REGULATORS. 1 : (AN) 7812 and 2 : (AN) 7912 AN7812 is the Positive Voltage Regulator. It regulates the voltage from (almost) 24vDC […]
1.2 – 15V/3A adjustable regulated power supply
https://www.electronics-lab.com/project/1-2-15v3a-adjustable-regulated-power-supply/
Specifications This kit provides a variable output power supply ranging from 1.2 to 15 V @ 3 A. It uses Low Dropout Positive Regulator LM1084 in TO220 package for delivering variable output voltage. Input – 18 VAC/DC Output – variable output from 1.2 ~ 15 V @ 3 A Regulated low ripple DC voltage Heatsink […]