Showing posts with label Speed Control Circuit. Show all posts
Showing posts with label Speed Control Circuit. Show all posts

Sunday, July 10, 2011

DC Motor Speed Control using PWM

The so-called PWM or Witdh modulation is a technique often used to control a load, for example, is the control of DC motor speed PWM techniques are used frequently.



Usually to make a simple PWM (for practice or the introduction PWM) fans to use some of the facts of the op-amp circuit, which consists of Schmitt Trigger circuit, the integrator and comparator.



DC Motor Speed Control using PWM

Schmitt Trigger function that produces a square wave will become the sawtooth wave or integrator is also called common rail and the ramp compared to a reference voltage that can change a lot of stress. So the result is a PWM output.



DC Motor Speed Control using PWM

These two schemes are variations of different circuit PWM. The diagrams are for 12V operation and there are upper (ground) and low side (+12 V common) versions. The version of the lower circuit uses an N-channel FET, the high-side version of the circuit uses a P-channel FET. N channel devices tend to handle more current P-channel devices, which are also less expensive. The version of the high side of the circuit is useful when a portion of the load must be grounded.



This circuit can change a fairly high amount of current, a MOSFET IRFZ34N can handle over 35 Amps if connected to an adequate heat sink. Higher power FETs, such as IRF1010Z IRFZ48N or can be substituted if even larger currents are required. It is also possible to connect multiple FETs in parallel even more current capacity. Always use thermally conductive grease between the FET and the heat sink, and remember that the heatsink is under stress.



Inductive loads (motors) may require special care because it can generate large voltage spikes that can damage the MOSFET. Replacing a 1N4002 fast recovery diode can help absorb the recoil reverse voltage when driving an inductive load like a motor. If you use these circuits to experiment with electric vehicles, be sure to install a circuit breaker in series with the battery, the switch should be easy to reach by the driver. This is especially important given the fact that when non-MOSFETs, is often cut, leaving the engine running at full speed

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Friday, May 6, 2011

Speed Fan Control Circuit using IC CD4017B

Speed Fan Control Circuit using IC CD4017BSpeed Fan Control Circuit using IC CD4017B Circuit

The simple abstraction activity is use IC CD4017 to ascendancy 4 relays which affix anniversary pole. IC CD4017B which is counter-cum-1kHz decoder and the arresting is disconnected into ten according intervals, Which can be programmed, via the distinct location, 10-mode.

According to the backward advertisement of the continuance of the acting period, the agnate achievement of the CD4017 inhibits adverse CD4017 (per pole of circling and diode D6), and fires the triac.

Here transistor T2 acts as a disciplinarian transistor. Pin by 4017, with aught at the achievement of the sensor for the about-face to 0(zero ascertain output) anniversary canyon through zero.

Remark. The accepted beachcomber forms of assertive positions of the rotary switch, as declared in EFY Lab are in the account 1.

The ambit is able to administer for a ambassador in the activity lighting equipment, hot air, oven singal Universal AC motor, heating, etc.

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