All Electronics Hobby Projects. You can build quickly them when have free times. Most cheap and easy to find parts.
LM317, 3A adjustable voltage regulator circuit diagram
Output: 1.2V to 20V, and 3V,6V,9V,12V
High quality, 3A adjustable voltage regulator. Using LM317 and 2N3055 so easy and cheap. Adjust voltage in steps 3V, 6V, 9V, 12V. And In fine, 1.25V to 20V.
This is a 0-60V, Dual Variable power supply circuit using LM317 and LM337 at 1.5A current so can builds to easy with PCB layout, adjustable voltage VR1,VR2 [...]
SEE! Many Power amplifier circuit diagram with PCB layout. So easy to builds. You can choose 0.5W to 1,200W. Using transistors, MOSFET, IC on a lot types
Simplest Automatic Solar Light from Water Bottle
This is simplest automatic solar led light circuit that my son try to make it for basic small solar charger. to use 2 x AA NI-MH battery total 2.4V
This is a 3A adjustable regulators using IC-LM350 that looks like LM317 Variable DC Power Supply, but high current higher 3A, adjust voltage 1.2V to 30V
This is simple Solar plant watering alarm circuit. It will sound alarms when the soil is dry. The trees have died. It the solar sell is 6V DC power supply
The special Relay that used replace normally relay, very fast contact load, low voltage input 3V to 24V only