Motor Control Circuits

Using MOSFETs would eliminate the drive power losses, but as can be seen by reviewing the performance of the best MOSFET presently available in SOT23 (see Figure 2), the on-resistance makes conduction losses very much higher than the total losses obtained using the FMMT617...

This hybrid circuit uses a mixture of transistors, an IC and a relay and is used to automatically open or close a pair of curtains. Using switch S3 also allows manual control, allowing for curtains to be left only partially open or closed. The circuit controls a motor which is attached to a simple pulley mechanism, to move the curtains. I first started this circuit over 20 years ago and apart from now using metal gears, very little has changed...

The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W), but almost anything you have to hand will work just as well...

The MOSFET speed controller presented here took over six months to design and fully test, back around 1988. I designed it from the ground up, as I found there were no suitable circuits or units available anywhere at the time. Those that had been published before either required unobtainable servo chips, or were so unstable as to be useless. I took one designed by a British hobby magazine to a race meeting once. It had been okay around home, but the interference from other radio gear at the race meeting rendered it useless. It relied on "floating" a derived triangle wave between two comparators...

If the transmitter stick-potentiometer delivers a voltage about 2 - 3 V, this circuit will be suitable. If you want to avoid using the battery cable (supplying Vcc for IC1and -2), you can use a separate 5V supply for IC1 and -2. In that case you should test the mixer function when the battery voltage is low...

No description available...

Controller for brushless and sensorless motors, with active rpm control # Active rpm control # Car mode # Proportional brake # Active freeweehling # Updates via Internet available..

For normal use it`s necessary to connect the battery, when the jumper is connected. Please take care, that the transmitter is on and the throttle is set to "power off"...

The controller is a prototype and works well in my plane with 7 cells and a Graupner-Speed 600...

Here is a reverse engineered diagram of this very typical circuit. Here should be a picture of the mechanism, Image description goes here...

This is a reasonably nice design...

This is the type that has a little DC motor fan positioned above a small container containing a deoderant liquid or jelly, and runs off a D cell...

This circuit can control a small DC motor, like the one in a tape recorder. When both the points A & B are "HIGH" Q1 and Q2 are in saturation. Hence the bases of Q3 to Q6 are grounded. Hence Q3,Q5 are OFF and Q4,Q6 are ON . The voltages at both the motor terminals is the same and hence the motor is OFF. Similarly when both A and B are "LOW" the motor is OFF. When A is HIGH and B is LOW, Q1 saturates ,Q2 is OFF...

Two small pushbutton switches, a few diodes and two relays form a method to control on/off power to a brush motor as well as the motor direction...

The layout using a BX-24 is almost the same as with a PIC and looks like the picture below (click for larger picture and comments). Read the source code for the BX-24 and study the picture and you should see how it all hooks up to the hex inverter and the SN754410...