This regulated power supply can be used to power up TTL and CMOS based projects, it provides 5 VDC & 12 VDC outputs with an onboard mains transformer. The project is based on the industry popular 78…
ExpressPCB
ExpressPCB circuit board layout program is a snap to learn and use. Laying out PCBs is easy, even for the first time user. Here are the steps: Select the Components Begin your layout by adding the co…
Unijunction Transistor (UJT)
Unijunction transistor (UJT), also called the double base diode, is a two layer. three terminal solid state (silicon) switching device. The device has unique characteristics that when it is triggered…
Fog Lamp Sensor Circuit
For several years now, a rear fog lamp has been mandatory for trailers and caravans in order to improve visibility under foggy conditions. When this fog lamp is switched on, the fog lamp of the pulli…
Flashing-LED Battery-Status Indicator Circuit
A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED D1 flashes to attire the user's attention, signaling that the circuit is ru…
Motor Bike Headlight Controller Circuit
This circuit automatically turns a motor cycle's headlight on and off, independently of both the light and ignition switches, provided the battery is fully charged. The first stage uses the 22O resis…
Car-Bulb Flasher
This astonishingly simple circuit allows one or two powerful 12V 21W car bulbs to be driven in flashing mode by means of a power MosFet. Devices of this kind are particularly suited for road, traffic…
Fog Lamp Switch Circuit
In most countries it is now mandatory or at least recommended to have a rear fog light on a trailer with the additional requirement that, when the trailer is coupled to the car, the rear fog light of…
Automatic Windshield Washer Control
Most, if not all, recent cars have an impressive amount of electronics, whether it be ABS brake systems, engine control with injection calculators, airbag activation, or other various functions, call…
Simple Headlight Reminders
These two headlight reminder circuits are easy to install and operate on the KISS (Keep It Simple Stupid) principle. The simple circuit involves adding just a 12V piezo buzzer between the lights circ…
LED Bike Light Circuit
On my mountain bike I always used to have one of those well-known flashing LED lights from the high street shop. These often gave me trouble with flat batteries and lights that fell off. As an electr…
Bicycle Speedometer With Hub Dynamo
Bicycle Speedometer With Hub Dynamo | Basic bicycle speedometer circuit consists of two parts: the cycle computer itself and a transmitter that is mounted on the front fork. A small magnet is attache…
Complementary Symmetry Push-Pull Amplifiers
The use of transformers, at input as well as at output ends, in the push-pull amplifier makes it bulky and expensive especially in this age of the integrated circuits. Another drawback of the circuit…
Phase Inverter / Phase-Splitter Circuit for Push-Pull Amplifier
In a push-pull amplifier circuit an input transformer is used to provide the polarity inversion between the two input signals to the push-pull circuit, but the transformer is quite expensive and bulk…
Class B Push-Pull Amplifier
The circuitry for the class B push-pull operation is the same as that for the class A operation except that the devices are biased at cutoff. The transistor in class B amplifier circuit is essentiall…
Infrared Proximity Detector Alarm
This circuit can be built from readily available low-cost components. The indicated value of 22 Ω for resistor R1 causes an average current of about 65 mA through infrared emitter D1. Because the IRE…
Power Buzzer
How often on average do you have to call members of your family each day to tell them that dinner is ready, it’s time to leave, and the like? The person you want is usually in a different room, such …
General-Purpose Alarm
The alarm may be used for a variety of applications, such as frost monitor, room temperature monitor, and so on. In the quiescent state, the circuit draws a current of only a few microamperes, so tha…
Electronics Projects/Circuits
Seven Segment Intruder Alarm Circuit Speed Checker for Highways Sensitive Intruder Alarm Circuit Electronic Fuse Circuit Simple Code Lock Smart Fluid Level Indicator Bass and Treble for Stereo System…
Simple Darkness Activated Alarm
Most darkness activated alarms employ op-amps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this time in monostable multivibrator mode. Components R2 and C1 r…
Model Railway Short-Circuit Beeper
Short circuits in the tracks, points or wiring are almost inevitable when building or operating a model railway. Although transformers for model systems must be protected against short circuits by bu…
Laser Alarm
This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and property. Essentially, when the beam gets interrupted by a person…
8051 Circuits
8051 Projects/Circuits: Line Follower Robot using 8051 Interfacing Hex Keypad to 8051 Interfacing Dot Matrix LED Display to 8051 Delay Using 8051 Timer Water Level Controller using 8051 Voltmeter usi…
Speed Alarm For Cars
In normal suburban driving you pass through so many different speed zones that it can be a nuisance having to switch speed settings. The speed display can also be a distraction. This circuit eliminat…
Night Alert
Idea of this circuit came to me at midnight when my pet dog started barking continuously on sensing a moving shadow, perhaps that of an intruder. Dogs have a night adaptation capability to maximise t…
Simple Knock Alarm With Piezo Sensor
This circuit uses a thin piezoelectric sensor to sense the vibrations generated by knocking on a surface; e.g, a door or table. Basically, it amplifies and processes the signal from the sensor and so…
Class B Power Amplifiers
In class B operation the transistor is so biased that zero signal collector current is zero. Hence class B operation does not need any biasing system. The operating point is set at cutoff, as illustr…
Class A Push-Pull Amplifier
A class A push-pull amplifier circuit is shown in Fig.1. A push-pull amplifier means that current flows in the output of the active device (each transistor) for the entire of the input cycle. Circuit…
Push Pull Amplifiers
Double-ended or push-pull amplifier makes use of two identical transistors in a single stage. It consists of two loops in which the transistor collector currents flow in opposite directions but add i…