Sine Wave Oscillator Circuit

To maintain oscillation the op. amp. must have a gain equal or exceeding this attentuation which is in fact x3. The desired gain is obtained by selecting the ratio of feedback resistance to input resistance of the inverting input (RV2 + R3)/R2. lf the overall gain, including feedback, exceeds unity the circuit will produce sine […]

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Simple Metal Detector Circuit

In this post we will how to make a simple metal detector circuit at home This metal detector is a low sensitive type  can be powered by a battery 3 to 15V, and may be constructed employing four exclusive OR gates from a CMOS integrated circuit 4030. The gates have been connected as two oscillators […]

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Simple Neon Flasher Circuits

The post details about a few simple neon flasher circuits The ionization potential of a neon used in the circuit is around 70V. To the extreme left of circuit 1, a neon is connected. A 0.47 microFarrad capacitor connected across the neon gets charged through a 1 MOhms resistor. The moment the voltage across the […]

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Water Level Controller Circuit using IC 555

The article tells us about a simple water level sensor with alarm circuit using IC 555. Here is a straightforward water level alarm circuit utilizing IC 555 clock that will deliver a perceptible alert when the water level compasses a preset level. The circuit can be controlled of a 3V battery and is exceptionally helpful […]

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Digital Volume Controller Circuit

The circuit shown here is based on the switching action of transistors. Volume of a stereo deck can be controlled with the help of a potentiometer which changes the resistance between the output of the preamplifier and input of the amplifier. This can be done with the help of decade counter, IC.4017 and some transistors. […]

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SCR Battery Charger Circuit

The post narrates a simple SCR based battery charger circuit for charging all types of batteries especially lead acid battery. Circuit Explanation A straightforward battery charger in view of SCR is demonstrated here. Here the SCR amends the AC mains voltage to charge the battery.In case the battery associated with the charger gets released the […]

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Accurate Analogue Frequency Meter Circuit

To measure frequency one does not  immediately have to ‘go digital’. The analogue approach will invariably prove simpler and cheaper, in particular when  the analogue readout (the multimeter)  is already to hand. All that is needed is n a plug-in device, a ‘trans1ator’, that will give the meter an input it can ‘under stand’. This […]

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Simple LED Voltmeter Circuit

This simple LED voltmeter circuit, although simple, is capable of accurate voltage measurement. The input is applied to the high impedance input of lC1 via the attenuator comprising of R1 to R5 inclusive. Since this IC is used as a unity gain buffer, the output at pin 6 is equal to the input voltage at […]

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Simple Logarithmic Amplifier Circuit

The performance of the logarithmic operational amplifier, the circuit diagram of which is shown in figure 1, is best seen from its input/output characteristic shown in figure 2. For small input voltages, the amplification is high; when the input voltage rises, the amplification drops off and finally remains almost static for further increases in input […]

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