Free electronic circuit design and schematic diagram
This is a Variable Q Twin-T Notch Filter circuit. This circuit is used when low Q is needed. The Lower Q gives some advantages in rejecting the signal where the signal deviate slightly from the null of the notch network. The Q of this circuit can be adjusted from 0.3 to 50. This circuit has two voltage follower. The second […]
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This is a Bootstrapped Twin-T Notch Filter circuit. This circuit can generate high Q by combining the twin “T” with LM102 voltage follower. The generated Q is greater than 50. This circuit uses small capacitors since the LM102 uses the large resistance values in the “T”. Beside that, voltage follower also used as buffer that gives high input resistance of […]
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Below is a circuit that demonstrates one use of an OTA using an LM13600. Take a note that the strange symbol stand for OTA. In this circuit, negative feedback is employed which is low-pass filter whose corner frequency can be electrically adjusted. We can a filter that would tune from 2700 Hz to 9000 Hz approximately for the values shown. […]
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This a Sallen and Key Lowpass Filter circuit. This circuit is a second-order active filter. This circuit can be changed to highpass filter by interchanging capacitors and resistors. This circuit is featured with buffer. The buffer of this circuit is op-amp which configured in inverting configuration. This circuit is stable, since this circuit has positive feedback and never overcomes the […]
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This is a Twin-T Notch Filter circuit. This circuit is a filter that can remove a certain frequency band. This is a passive filter that uses two filters in parallel, high-pass and low-pass. The high-pass filter is lower one and the low-pass filter is the upper one. This filter has a problem with the input resistance. When this filter is […]
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This is a complement phase inverter circuit. Sometimes this circuit called a paraphase amplifier circuit. This circuit has two output signals that is have sufficient “headroom” because this circuit is biased. The transistor will be saturated when the collector decreases, the emitter voltage increases and set the limit. Here is the circuit: This circuit can produces a peak to peak […]
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This audio mixer is built with transistors. This audio mixer circuit is unique, not based on low input impedance amplifier. Most of audio mixer circuit is based on low impedance amplifier, so a high resistance signal source point can be summed together without disturbing each other. This mixer circuit is different, since the circuit is based on something like open […]
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