Simple Game Circuit

This is a very simple game circuit. You can play this with your friends. To win this game one has to scores hundred points in very short time. Incase if you want to restart the game you need to press S1 button switch.

When supplies the output voltage make sure you do not use over 5 Volts as it can damage the components. We recommend you to use copper PCB board to build this circuit. Also we do not recommend any of our circuits for kids who do not familiar with electronics and live current.

As you can see in the circuit diagram the it operates by three ICs. Try to use good quality  switches for long durability.

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Simple NiCd Battery Charger

A simple NiCd charger can be built using ‘junk box’ components and an inexpensive LM317 or 78xx voltage regulator. Using a current limiter composed of R3 and a transistor, it can charge as many cells as desired until a ‘fully charged’ voltage determined by the voltage regulator is reached, and it indicates whether it is charging or has reached the fully charged state. If the storage capacitor (C1) is omitted, pulsed charging takes place. In this mode, a higher charging current can be used, with all of the control characteristics remaining the same. The operation of the circuit is quite simple. If the cells are not fully charged, a charging current flows freely from the voltage regulator, although it is limited by resistor R3 and transistor T1.

The limit is set by the formula Imax ≈ (0.6 V) ÷ R3 For Imax = 200 mA, this yields R3 = 3 Ω. The LED is on if current limiting is active, which also means that the cells are not yet fully charged. The potential on the reference lead of the voltage regulator is raised by approximately 2.9 V due to the voltage across the LED. This leads to a requirement for a certain minimum number of cells. For an LM317, the voltage between the reference lead and the output is 1.25 V, which means at least three cells must be charged (3 × 1.45 V > 2.9 V + 1.25 V). For a 78xx with a voltage drop of around 3 V (plus 2.9 V), the minimum number is four cells.

When the cells are almost fully charged, the current gradually drops, so the current limiter becomes inactive and the LED goes out. In this state, the voltage on the reference lead of the regulator depends only on voltage divider R1/R2. For a 7805 regulator, the value of R2 is selected such that the current through it is 6 mA. Together with the current through the regulator (around 4 mA), this yields a current of around 10 mA through R1. If the voltage across R1 is 4 V (9 V – 5 V), this yields a value of 390 Ω. The end-of-charge voltage can thus be set to approximately 8.9 V. As the current through the regulator depends on the device manufacturer and the load, the value of R1 must be adjusted as necessary. The value of the storage capacitor must be matched to the selected charging current. As already mentioned, it can also be omitted for pulse charging.

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Simple 50 to 300 MHz Colpitts Oscillator Diagram

Simple high efficiency Colpitts oscillator .In the higher frequency ranges, above 50 MHz, Colpitts oscillators are used because stray circuit capacitance will be in parallel with desired feedback capacitance and not cause undesirable spurious resonances that might occur with the tapped coil Hartley design.

The FM VCO shown is a grounded base design with feedback from collector to emitter. A Colpitts oscillator is one of a number of designs for electronic oscillator circuits using the combination of an inductance with a capacitor for frequency determination.As you can see in the circuit diagram , this electronic project require few electronic parts an provide a 50 MHz-300MHz VCO with a tuning range of 2:1 .

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Simple Bass Treble Tone Control

The LM1036 is a DC keep watch overled tone (bass/treble), quantity and balance circuit for stereo utilitys in automotive radio, TV and audio methods. An extra keep watch over enter permits loudness compensation to be merely effected. Four keep watch over enters present keep watch over of the bass, treble, balance and extent operates thru application of DC voltages from a faraway keep watch over device or, however, from four potentiometers which is also biased from a zener regulated provide provided on the circuit.

Circuit diagram :

Bass Treble Tone Control Circuit Diagram

Each tone response is outlined by means of a single capacitor chosen to offer the specified attribute.
Features:

• Wide supply voltage range, 9V to 16V
• Large volume keep an eye fixed on vary, seventy five dB typical
• Tone regulate, ±15 dB typical
• Channel separation, 75 dB typical
• Low distortion, 0.06% typical for an enter degree of zero.3 Vrms
• High signal to noise, 80 dB standard for an input stage of 0.3 Vrms
• Few exterior parts required

Note:
Vcc can additionally be anything between 9V to 16V and the output capacitors are 10uF/25V electrolytic

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Simple Remote Doorbell Warning Switch Circuit

This circuit should only be used with the solenoid type chime doorbells, the electronic type that play tunes will not work here. This is the simple circuit design.


The basic principle work is the hardest part for this circuit was the title. It is quite easy to miss the sound of a doorbell if you are watching the television, this circuit gets round the problem by providing a visual indication, i.e. a lamp. As an alternative, a LED could also be used. You could just parallel a lamp across the doorbell, but this would mean extra drain from the doorbell batteries or transformer.

Using a series resistor R1 actually reduces current flow, and if run from batteries, will give them a longer life. The value of R1 is chosen so that about 0.6 to 0.7 volts is dropped across it, and the doorbell should still ring. I used a combination of a 22 ohm resistor in parallel with a 50 ohm. The doorbell still rang and circuit operated correctly. I used to have an electromechanical counter that registered each time when someone pressed the switch.

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