Free electronic circuit design and schematic diagram
This is a motor controller circuit that control the speed and direction of series-wound Motors. This circuit employs silicon controlled rectifiers (SCR) Q1-Q4, that are triggered in diagonal pairs. The switch St is used to control which pair is turned on because either coupling transformer T2 or coupling transformer T1 is connected to a pulsing circuit by this switch. Here […]
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It will be effective to use simple half wave motor speed control with small universal ac/dc motors. Two amps RMS is the maximum current capability. The control gives excellent torque characteristics to the motor because speed dependent feedback is provided, even at low rotation speeds. By closing switch S1, thus bypassing the SCR, we can achieve normal operation at maximum […]
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National LM378 amplifier is used as a basis for economical proportional motor speed controller. This integrated circuit is able to deliver 700 mA continuous current for such DC motor applications such as antenna rotors or motor controlled valves. The basic of proportional control is as simple as amplifying the error signal to produce an action in such direction that minimize […]
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This is a schematic diagram of Permanent Magnet Motor Control circuit. This circuit is used to control the permanent magnet control. This circuit uses alternistor triac to enhance commutation characteristics because the PM motor is a generator where the standard triac difficult to commutate properly. The full-wave DC rectification is needed for PM motors. Here is the schematic diagram of […]
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Another example of frequency-to-voltage converter application similar with RPM/Speed Indication is motor speed control. Here the converter is used to measure the actual speed which will be fed back to keep the actual speed stabilized according to a reference. Here is the block diagram of this control system: If the speed is to high, the output of the F/V converter […]
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To provide rapid motor speed changes and motor direction reversal, four outputs drive a MOSFET H-bridge. N-channel devices are the lower rail power MOSFETs and P-channels are the upper MOSFETs. All of them are driven by the TC4469. A small series resistor helps prevent gate oscillation and slows transition time in the lower rail devices, helping the upper device to […]
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This is a 230VAC Temperature Fan Control circuit. This circuit is used for 230Vac operation. The R9 can be changed to 15K 2W, if the AC operation is 115V. This circuit uses the principle of Wheatstone bridge. The Wheatstone bridge is made from R3-R4 and R1-P1. P1-R1 produce a temperature-sensitive “variable” voltage and a fixed two-thirds-supply “reference” voltage is produced […]
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