Fault finding in complicated mains wirings often becomes a hard nut to crack for every electrician involved in the business. The simple circuit idea presented here can surely help them to get rid of headaches accompanied during such tedious assi… Read more »
The circuit is designed to use very little current to prolong battery life so that it can be left on permanently. A superbright’ red LED is used because this provides a bright flash with a low current. If you want to use 4.5V supply by connecting… Read more »
When reading schematics, repairing radios and buying capacitors, you often must convert between uF, nF and pF. Paper and electrolytic capacitors are usually expressed in terms of uF (microfarads). Short forms for micro farad include uF, mfd, MFD, MF… Read more »
Design By Sunil Inconvenience in switching on a water pump installed in a remote farm is a common problem faced by farmers. Many circuits have been developed to solve this problem. Most of them are expensive and microcontroller-based. Here we pr… Read more »
Improved bike headlight switch circuit presented here has been designed to switch bike headlight on (or similar loads) at a presettable ambient light level. The circuit is based on the renowned timer chip LM555 (IC1), here triggered by a d… Read more »
This light activated relay circuit presented here uses the 555 timer IC and a light dependent resistor or LDR to form a light sensitive relay in an intruder alarm system or for switching on a lamp at Sun set and off at Sun rise. Potentiometer R1 v… Read more »
This circuit delivers an initial voltage of 2.5V per cell to rapidly charge a car battery. The charging current decreases as the battery charges and when the current drops to 180 mA the charging circuit reduces the output voltage to 2.35 V per cel… Read more »
This PSU has been especially designed for current-hungry ham radio transceivers. It delivers safely around 20Amps at 13.8V. For lower curren… Read more »
If 3rd band is gold, Divide by 10 If 3rd band is silver, Divide by 100 (to get 0.22ohms etc) … Read more »
This constant current circuit is designed to drive two 3-watt Luxeon LEDs. The LEDs require 1,000mA (1Amp) and have a characteristic voltage-drop across them of about 3.8v. Approximately 4v is dropped across the LM317T regulator … Read more »
Circuit takes 70mA on LOW brightness and 120mA on HIGH Brightness This circuit has been specially designed for a 6v rechargeable battery or 5 x 1.2v NiCad cells. Do not use any other voltage. It has many fe… Read more »
Here's an interesting circuit that creates a clock pulse for a 4017 from a flashing LED. The flashing LED takes almost no current between flashes and thus the clock line is low via the 1k to 22k resistor. When the LED flashes, the voltag… Read more »
This is the circuit in a $2.00 Solar Garden Light. The circuit illuminates a white LED from a 1.2v rechargeable cell. … Read more »
These three circuits flash the left LEDs 3 times then the right LEDs 3 times, then repeats. The only difference is the choice of chips. … Read more »
This circuit can be used to indicate left and right turn on a motor-bike. Two identical circuits will be needed, one for left and one for right. … Read more »
This circuit produces traffic lights for a "4-way" intersection. The seemingly complex wiring to illuminate the lights is shown to be very simple. … Read more »
Here's a clever circuit using two 555's to produce a set of traffic lights for a model layout. The animation shows the lighting sequence and this follows the Australian-standard. The red LED has an equal on-off period and when it is off, … Read more »
This circuit flashes two red LEDs for a model railway crossing. … Read more »
The value of the current limiting resistor can be worked out by Ohms Law. Here are the 3 steps: 1. Add up the voltages of all the LEDs in a string. e.g: 2.1v + 2.3v + 2.3v + 1.7v = 8.4v 2. Subtract the LED voltages from the supply vol… Read more »
