What is a Zener Diode
Diodes are electronic components which will let current flow in just one direction. They are used for example in PV Solar Panel installations to ensure that current can flow into the battery bank when it is sunny, but not escape through the solar panel when …

Switch from Inverter to Mains Automatically
The majority of domestic renewable energy is generated to supplement an existing mains power supply - for example, an array of solar panels used to reduce the costs of powering a home. Unfortunately the cost of grid tie inverters with UK G83 approval (and professional installation) …

High Current Voltage Regulation
Voltage regulators are available as easy to use three terminal integrated circuits - one terminal for the input voltage, one for the output voltage, and one for the ground (0V). The most commonly used are from the 78XX series - 7812 for 12 Volts, and …

LM317 High Current Voltage Regulator
The LM317T is a very useful adjustable voltage regulator which will take in an input from 3-40 Volts DC, and output from 1.2-37 Volts DC. The output voltage is set simply using a couple of resistors. The LM317T is rated to output (subject to correct heat …

Using The LM317T To Regulate Voltage
The LM317T Voltage Regulator is an integrated circuit which is very useful in many renewable energyapplications. It can be used to regulate current - for example to regulate the current in a string of LEDs - or it can be used to provide a stable …

LM317 Adjustable Power Supply
In our article LM317 Voltage Regulator we introduced the LM317 which can provide a regulated output voltage from 1.2-37V from an input voltage of 3-40V, with the output voltage set simply with a couple of resistors. In this article we will show how this IC can …

Light Dependent Resistor
A Light Dependent Resistor (aka LDR, photoconductor, photoresistor, or photocell) is a component used commonly in electronics which has a resistance which decreases as the intensity of the light hitting its surface increases and visa versa. A typical light dependent resistor is pictured above together …

What is a Shunt
A shunt (aka a current shunt resistor or an ammeter shunt) is a high precision resistor which can be used to measure the current flowing through a circuit. Using Ohm's Law we know that the voltage dropped across a resistor divided by the resistance of …

Simple Low Voltage Disconnect with NE555
In our article Low Voltage Battery Disconnect Circuits we explained how a low voltage disconnect (LVD) is a circuit designed to automatically disconnect loads from a battery when the battery voltage is low thereby protecting the battery from being damaged by being overly discharged. While we …

Low Voltage Battery Disconnect Circuits
A low voltage battery disconnect (LVD) is a circuit which will automatically turn off the load connected to a battery if the battery voltage falls to low. Preventing lead acid batteries from being deeply discharged is absolutely key in terms of ensuring battery longevity. We sell …

LM317 Voltage Calculator
The LM317 (LM317T), and high current LM338 (LM338T) are voltage regulators which can take an input voltage of 3-40 Volts DC, and output a fixed output voltage from 1.2 to 37 Volts DC. The output voltage from the LM317 and LM338 is set using two resistors …

LM317 Current Calculator
In our article Using the LM317 with LED Lighting we looked at how the LM317T (and high current equivalent LM338T) can be used to supply a fixed current to a load - in the case of the article to LED bulbs. The output current from the …

Zener Diode Voltage Regulator
A Zener Diode is an electronic component which can be used to make a very simple voltage regulator circuit. This circuit enables a fixed stable voltage to be taken from an unstable voltage source such as the battery bank of a renewable energy system which …

12 Volt Battery Monitor Circuit With LM3914
In our article Make a Simple Battery Status Monitor we showed how a few components could be put together to make a very basic battery voltage monitor to give a visual indication of the charge state of a 12V lead acid battery. Here we will show …

Germanium Diodes
Diodes are a very important component of most alternative energy generating systems - for example in PV solar panels they are used to stop energy being radiated back out into the night sky from the battery bank, and in wind turbine generators they are used to …

LM2940 12V 1A Low Dropout Regulator
Many 12V-rated devices can be damaged by being exposed to voltages in excess of 12 Volts - particularly LED lights which have a maximum working voltage typically of 13.5 Volts. Nominally 12 Volt Lead acid batteries typically operate in the range of 12.6V (40% charged) to …

LM317T Heatsinking
The LM317T is an adjustable voltage regulator chip in a TO-220 package (as pictured below). This chip can be used to supply a load current of up to 1.5 Amps at 1.2 to 37 Volts (from an input of 3 to 40 Volts). The larger the …

Smoothing Capactitors
A capacitor is a device which stores electrical charge - basically it stores electrons. In the most simple terms it can be thought of as being similar to a rechargeable battery in that it stores power to be used at a later time. Charging a …

DC Voltage Multiplier Circuit Plans
A DC voltage booster, DC voltage multiplier, or DC-DC Step-Up Converter is a very useful tool which enables a low source DC voltage to be boosted (stepped up) to a higher output DC voltage which is more useful. For example, ultrabright LEDs need a 2.5-3.5 Volts …

Making Voltage Doublers and Multipliers
A voltage doubler or voltage multiplier is a circuit easily made from a few components which enables the voltage from an AC power source to be increased. This is particularly useful in situations where the load current is low, but a higher voltage than is …

Make a Shunt Resistor
A shunt resistor (pictured below) is a high-precision resistor of very low resistance used by anammeter to measure the current flowing through an electric circuit. Shunts are available in a range of sizes from under one Amp to many hundreds and thousands of Amps, but …

Automotive Relays
Relays are a vital component of many renewable energy applications, particularly where the output from a low voltage low current electronic controller is used to switch a high current device such as a pump, motor, or heater. For applications where a load current of under 10 Amps …

Reducing Relay Power Consumption
While relays are very useful for switching things on and off, for situations where power consumption is to be kept to a minimum, the power used by the relay itself can be a problem - for example where a small LED light is to be …

Automatic Hen House Door Closer Opener
An automatic hen house door opener and closer is very useful for anyone who keeps hens and cannot guarantee they'll be able to manually open or close the door every day. Simple systems have a light detector and the door is opened at dawn and …

Relays and Renewable Energy
A relay is a type of electrically operated switch which is controlled by an electronic circuit. Within the relay is a coil of wire which generates a magnetic field when a current flows through it. If sufficient current at the correct voltage flows through the …

Three Phase Bridge Rectifier
Most wind turbine and hydro permanent magnet alternators output three phase alternating current (AC) electricity. In order to get this generated power into a battery bank, it must first be rectified into direct current (DC) electricity. Through our website we have many articles which explain how …

Stepper Motor Voltage Doubler
A stepper motor can be used in conjuction with PVC rotor blades to make a very cheap DIY wind turbine generator. Stepper motors can be bought new quite cheaply, but they can also be salvaged out of old printers, floppy disk drives, and other sources. Learn …

Convert External PIR To Low Voltage
There are many affordable mains powered outdoor rated PIR sensors available, and many affordable low voltage indoor rated 12V Pir Sensors, but there are very few low voltage outdoor rated PIR sensorsavailable and those which are available tend to be quite expensive - typically 3x …

LM2941 1A Low Dropout Adjustable Regulator
We frequently receive requests for voltage regulators for systems for which the common LM317 is not suitable. Although the LM317 can accept input voltages up to 3-40 Volts, and output regulated voltages from 1.2-37 Volts, it can only output a reliable fixed voltage if the …

New Simple Hen House Door Controller
In our article Automatic Hen House Door Closer/Opener we showed how to overcome the difficulty of getting a motor to turn one way to open a door and turn the opposite way to close a door. We offered programmable timer based and light detector based products …

Making a Bridge Rectifier
A Bridge Rectifier is an essential part of any home made (DIY) wind turbine generator (or Water Wheel). A bridge rectifier converts the alternating (AC) current generated into Direct Current (DC) which can be sent to a battery bank. Low voltage wind turbine generators e.g. 12 …

Bridge Rectifier
For most alternative energy applications, we require a direct current (DC) voltage to be generated - for example to charge a bank of batteries. However wind turbines and wave power generators create an alternating current (AC) voltage. This is where the Bridge Rectifier comes in. …

Relay Boards
A relay is a kind of switch which is controlled by an electric current. A relay makes it possible for a low voltage low current circuit to switch a high voltage and/or high current device safely - for example, a small battery-powered light detector circuit …

Three Phase Voltage Multiplier
Whether you make your own small DIY wind turbine alternator or use a stepper motor to generate electricity, one common problem is that the generated voltage is too low to be used to charge a 12 Volt battery. In our article stepper motor voltage doubler circuit …

Resistor Colour Codes
The humble resistor is a key component of many renewable energy systems. They are designed to resist electricity and can therefore be used to supply the correct voltage or a suitably limited current to the various components in an electric circuit. Because resistors are so small …

Reverse Polarity Protection
With any circuit connected to a battery or other DC power source there is always the risk that you or someone will inadvertently connect it with reverse polarity - i.e. connect the positive from the power source to the negative input of the circuit and …

Fixed Voltage Regulators
In a previous article we covered how the LM317T voltage regulator chip can be used to obtain a fixed voltage from a variable supply. Looking at a typical renewable energy system 12V battery bank, the output from the batteries can rise to 15V+ when they …

Ohm's Law
If you are going to learn anything about electric circuit principles then Ohm's Law should be top of your list. With Ohm's Law you can make calculations to quantify the power, voltage, current, and resistance in renewable energy systems with ease. Above is a handy chart …

Basic Ammeters and Voltmeters
In even the most basic renewable energy system it is essential to monitor the charge in the battery bank, the voltage and current coming from the generator, and the current being drawn by the power inverter or other loads. In this article we will cover …

What Is A Thyristor
In our article What is a Transistor we looked at transistors. A thyristor (aka Silicon Controlled Rectifier or SCR) is similar to a transistor in that a small input current into one pin switches a much larger current across two other pins - a small …

Use Thermostat As 12 Volt Timer
As we have previously discussed in our article 12 Volt Programmable Timer Switch, it is not possible near impossible to purchase a programmable timer which can be powered directly from a battery bank used to switch on and off connected devices. Programmable Thermostat Most domestic central heating …

Light Dark Dawn Dusk Relay Controller
We have for many years been selling our high current light dark sensor circuit and low current light dark sensor circuit which are based around the simple LM741 Light Dark Sensor Circuit for which we provide the circuit design on our website. During that time we …

Switch Mains Powered Appliances Safely
One problem we come across a lot is people wanting to control mains powered appliances using low voltage circuits - for example to power pumps for automatic irrigation systems, pumps for solar heating systems, and with our light detector, motion detector, and timer circuits. Usually …

Renewable Energy Powered Timer Relay Switch
In our articles Use Thermostat as 12 Volt Timer and Convert Thermostat to 12V Timer Switch we looked at how a cheap battery powered programmable thermostat could be converted for use as a timer relay switch. This system works very well and there are now …

Reed Switches
A reed switch consists of a sealed glass tube containing a pair of ferrous metal contacts. When a magnetic field comes close to the reed switch, the two contacts come together enabling a current to pass through the switch. Most commonly reed switches are used …

 

LM317 Voltage Calculator
A handy online output voltage calculator for the LM317, LM338, and other linear voltage regulators
Article Last Modified: 00:06, 25th Sep 2014
electric circuit | electronics | general

Using The LM317T To Regulate Voltage
Use an LM317T to regulate voltage in renewable energy projects
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics

Using The LM317T With LED Lighting
Use an LM317T to regulate the current in LED lighting projects
Article Last Modified: 23:21, 24th Sep 2014
lighting | electric circuit

Three Phase Bridge Rectifier
Find out about three phase bridge rectifiers
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | storage | general

Three Phase Basics
Get an understanding of three phase wiring in wind turbine alternators
Article Last Modified: 23:21, 24th Sep 2014
wind | electric circuit | websites

Three Phase Voltage Multiplier
The Cockcroft-Walton turbine voltage multiplier
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | wind | general

Stepper Motor Voltage Doubler Circuit
Double the voltage from a stepper motor using two bridge rectifiers
Article Last Modified: 23:21, 24th Sep 2014
general | electric circuit | education

Sump Pump Control System
Put together a fully automatic system to reliably pump out the water collected in a sump pit
Article Last Modified: 23:21, 24th Sep 2014
water | electric circuit | electronics

Solar Powered Nestbox CCTV Camera
Observe wildlife inside a nestbox with a solar powered wireless CCTV camera
Article Last Modified: 23:21, 24th Sep 2014
solar | electric circuit | general

Solar Shed Lighting Circuit Testing
Analysis of a typical solar shed LED lighting circuit
Article Last Modified: 23:21, 24th Sep 2014
lighting | solar | education | electric circuit

Smoothing Capacitors
Find out more about the uses of smoothing capacitors in renewable energy circuits
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | education

Simple Well Pump Controller
Find out how to automatically get water from the well into a header tank
Article Last Modified: 23:21, 24th Sep 2014
water | electronics | electric circuit

Solar Battery Charger With LM317T
Find out how to make a current controlled solar battery charger using an LM317T
Article Last Modified: 23:21, 24th Sep 2014
solar | education | electric circuit

Solar Charge Controller
Find out more about Solar Charge Controllers
Article Last Modified: 23:21, 24th Sep 2014
solar | electronics | electric circuit

Simple Sump Pump Controller
Put together a sump pump controller with two float switches and NO electronics
Article Last Modified: 23:21, 24th Sep 2014
water | electric circuit | electronics

Repeat Timer Circuit
Make a repeat timer circuit with large intervals between ON times
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | general

Renewable Energy Powered Timer Relay Switch
Powering an AA battery powered timer thermostat directly with a 12V power source
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | general

Resistor Colour Codes
Learn how to identify different resistors with their colour code
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | education

Relays and Renewable Energy
Find out more about relays and their uses in renewable energy applications
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | general

PIR Sensor Circuits
PIR sensor circuits ideal for use within renewable energy applications
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | general | solar

Ohms Law
Learn about Ohm’s Law and how it is used in Renewable Energy systems
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | education

Minimising Line Losses in RE Systems
Select wire of the correct diameter for your renewable energy system
Article Last Modified: 23:21, 24th Sep 2014
storage | electric circuit

Optocouplers
Find out more about optocouplers/optoisolators and their uses
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | education

Making Voltage Doublers and Multipliers
Find out how to construct an AC voltage doubler circuit. Extend it to a tripler circuit and more.
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | education

LM741 OpAmp Voltage Indicator
Plans for a simple voltage high/low indicator built around an LM741 operational amplifier
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | general

LM741 Light Dark Sensor Circuit
Build a light/dark sensing circuit to automatically turn on/off lights and other devices
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | general

Light Dark Dawn Dusk Relay Controller
Find out about the REUK Super LDR light/dark dawn/dusk relay controller
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | news | shopping

LED Dimmer Circuit
Find out how to put together a simple but efficient PWM dimmer circuit for LEDs
Article Last Modified: 23:21, 24th Sep 2014
lighting | electronics | electric circuit

Light Dependent Resistor
Find out more about LDRs and their use in renewable energy and other projects
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | solar

LM317T Voltage Regulator Chip
Learn about the LM317T and its uses in renewable energy projects
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit

Latching Relays
Find out about latching relays and their uses
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | general

High Capacity Alternative to 9 Volt Battery
Get ten times the capacity of a 9 Volt battery to power your devices
Article Last Modified: 23:21, 24th Sep 2014
general | electric circuit | solar

High Current Voltage Regulation
Connect voltage regulators in parallel to increase the current which can be regulated
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | general

Hacked PIR Sensor
Cannibalise a cheap PIR sensor to put it to other uses
Article Last Modified: 23:21, 24th Sep 2014
electronics | education | electric circuit

Fixed Voltage Regulators
Use a voltage regulator to obtain a fixed voltage supply (at <1.5 Amps) from a variable source
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics

Dual Powered Lighting Circuit
Power a lighting circuit from renewable energy or mains electricity
Article Last Modified: 23:21, 24th Sep 2014
lighting | electric circuit

DC Voltage Multiplier Circuit Plans
Build a circuit to boost the voltage of a DC power source using a MAX756 IC Chip
Article Last Modified: 23:21, 24th Sep 2014
electric circuit | electronics | education

Connect Multiple PIR Sensors Together
Find out how to connect up two or more PIR sensors to one relay board or microcontroller input
Article Last Modified: 23:21, 24th Sep 2014
electronics | electric circuit | general

Automatic Pump Shut Off Circuit
Put together an automatic system to switch off a pump when there is no more fluid left to pump
Article Last Modified: 23:20, 24th Sep 2014
water | electric circuit

Automatic Hen House Door Closer Opener
Find out how to put together a DIY automatic hen house door opener and closer
Article Last Modified: 23:20, 24th Sep 2014
electric circuit | general | solar

Automotive Relays
Find out more about automotive relays and their use in renewable applications
Article Last Modified: 23:20, 24th Sep 2014
electric circuit | general

AWG to Square mm Wire Size Converter
Convert between AWG, inches and mm diameter, and square mm area measures of wire size
Article Last Modified: 23:20, 24th Sep 2014
storage | electric circuit

40 Amp Blocking Diode 1N1190A
Find out how to use a blocking diode with a wind turbine generator
Article Last Modified: 23:20, 24th Sep 2014
wind | electric circuit | solar

24V 12V DC DC Converter
Find out how to use a 24V battery to power 12V devices
Article Last Modified: 23:20, 24th Sep 2014
storage | electric circuit

Adjustable Step Up Voltage Regulator
Find out more about a step up voltage regulator used to output a voltage higher than the input voltage
Article Last Modified: 23:20, 24th Sep 2014
electronics | electric circuit | general

12 Volt Battery Low Indicator LM741
Plans for a battery low indicator for a 12 Volt battery using an LM741 operational amplifier
Article Last Modified: 23:20, 24th Sep 2014
electronics | electric circuit | general

12 Volt Battery Monitor Circuit with LM3914
Accurately monitor battery voltage with LM3914 LED bar graph driver
Article Last Modified: 23:20, 24th Sep 2014
storage | electric circuit | education