Category Archives: Fun Circuits



Circuit For Quiz Contest : Electronic Jam

This is the design diagram of electronic jam. This jam circuit can be implemented in quiz contests in which any participator who pushes his switch (button) prior to the other participants, will get the first opportunity to answer a question. The circuit provided right here allows up to eight participants with each one assigned a… Read More »

Portable 230V Lamp Flasher

This is a portable, 230V high-power incandescent electric lamp flasher circuit diagram. It is actually basically a double flasher (alternating blinker) which could manage two different 230V AC loads (bulb lamps L1 and L2). The circuit is completely transistorised and battery-powered. The free-running oscillator circuit is realised working with two low-power, low-noise transistors T1 and… Read More »

Electronic Horn

This is an easy, low cost and easy built circuit of an electronic horn which is designed close to quadruple op-amp IC LM3900 (IC1). IC LM3900 has four independent operational-amplifiers (A1 through A4) having a large output voltage swing. It is able to operate at up to 32V DC. The 1st op-amp (A1) is designed… Read More »

Ticking Bomb Sound Generator

Here the low cost and easy build circuit of ticking bomb sound generator. This circuit generates a sound matching to a loud clicking clock. The frequency of the tick is altered through the 220k potensiometer part. The circuit gets going by charging the 2.2uF and when 0.65v is on the base of the NPN transistor,… Read More »

White Line Follower

This is the circuit diagram of white line follower toy. The actuator of the toy is the DC motor. This circuit can be used for a toy car to follow a white line, this circuit also known as very simple robot: “line follower without microcontroller”. The motor is either a 3v type with gearing to steer the car or… Read More »

Low-Cost and Simple Intercom

This is a low-cost and simple intercom circuit design. Some intercom circuits is build by applying integrated circuits. The circuit described right here utilizes 3 certainly transistors which easy to find on the electronic store. Even a newbie can assemble it on a piece of veroboard without difficulty. The circuit consists of a 3-stage resistor-capacitor… Read More »

Telephone Ringtone Generator

This is really a very simple home telephone ring tone generator circuit which is built with applying only several electronic components / parts. It generates simulated telephone ring tone and requires only DC supply with 4.5V DC to 12V DC voltage. One may possibly use this circuit in ordinary intercom or phone-type intercom. The sound… Read More »