Free electronic circuit design and schematic diagram
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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Ionization-based smoke detectors are efficient and cheap, so they are often installed in the house, other outbuildings, and the garage. The Locations of the device is far from house, so we need to transmit the alarm signals back into central home-security system or the house. This is a simple circuit that sense a supply current increase because activation of smoke […]
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This circuit is made to be an alarm, both for home and handbags. If it is installed for home it will placed on door or windows, and if it is installed for bags or handbags it will placed in the bag. This circuit consists of a small magnet and a reed switch. If the magnet looses its contact with the […]
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Our reader Andrea (andrea[dot]perugia[-at-]gmail[dot] com) sent his circuit to us, and he creates the circuit for educational intent. The main purpose is to show that you can toggle an output state electronically, although physically you use only a push button switch. Here is what he said about the cicuit : This simple circuit can be utilized to drive a monostable […]
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Autoranging is useful to extend the measurement range of an available ADC (analog-to-digital converter). Autoranging will best implemented for multiplexed input. LTC1257 is appropriate for system autoranging, adjusting an ADC’s full-scale range. During the conversion process, U2 and U3 receive the full and zero scale codes, respectively, that correspond to a selected multiplexer channel. For example, let channel 2’s span […]
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Computer-controlled 4-20mA current loop is useful to control some industrial equipments. By current loop, transmitting the signal over long distant should be resistant from noise interference. This computer-controlled 4 – 20mA is designed to operate on a single supply over a range of 3.3V to 30V. The zero reference of 4 mA is set by R1 and calibrated using R2. […]
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Stepper motor gives a simple, low cost, and accurate position control. Stepper motor can be driven by circuit mounted close to the motor, and controlled by a remote control circuit through long cable. The interesting thing of this circuit is that the power for both motor and the driver circuit is carried over two wires, the same wires that carry […]
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