Free electronic circuit design and schematic diagram
This is a HI-FI tone control circuit with high Z input. This circuit is used to control HI-FI tone. Here is the circuit: To buffer op-amp operated feedback type tone control circuit, this circuit uses 2N3684 JFET. The 2N3684 JFET is implemented on this circuit because it has low noise characteristics and provides the function of a high input impedance. […]
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This is a simple FET Cascode Video Amplifier circuit. This circuit has some features, they are reduction of feedback to almost zero and very low input loading. Here is the circuit: This circuit uses 2N3823 because it has high Yfs and low capacitance. RL and load capacitance limits bandwidth of the amplifier. [Source: National Semiconductor Application Note]
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This is an ultra high input impedance AC unity gain amplifier circuit. This circuit is used to get unity gain from ultra high input impedance AC. Here is the circuit: Because we can’t reduce input capacitance of this circuit, so we use the 2N4416 which has low capacitance. It is operated as a source follower with bootstrapped gate bias resistor […]
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This is a simple circuit that can be used to convert a low-voltage PWM signal into a buffered and amplified linear output. This circuit is designed for fan speed control. It uses PWM outputs to control fan speed as a function of temperature. Here is the circuit: As a linear amplifier, this circuit uses a PMOS FET (Q2) and a […]
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The large issue today that caused by more electronic equipment enters the home and the office is noise of fan. to reduce fan noise, a variable speed fan is used because it permits quieter and slower, fan speed when temperature conditions allow. To build a variable speed fan we can use digital control or high-speed/low-speed switches. Digitally controlled fans perform […]
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This is a circuit that transmits temperature data over an IR link and it allows the isolation of temperature sensor. It is a good solution of obtaining temperature readings from points at potentials a few tens of volts from ground by linking a temperature probe only by an IR connection to the readout point. This circuit consist of a temperature […]
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We usually use a fan to manage the temperature, but it produces audible noise at full speed. To reduce this noise we can use this circuit. The first circuit reduces the noise by controlling the cooling-fan speed as a function of temperature. It uses an IC that combines temperature sensing with a PWM output. When the temperature of the processor […]
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