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No-Hum Fan Controller - Control is derived from the output of regular wall switch. The signal is filtered to obtain the dimming level as a low level analog voltage by C3 and its associated components. The LM3914 chip selects one of its outputs depending on the amplitude of the voltage, which turns on one of the LEDs to indicate the speed, and turns on one of the Solid State Relays to control the fan speed. The LEDs allow a handy display of the speed. The top LED (green) shows full power to the fan __ Designed by Ed Cheung Nu-based stepper Motor drive - A nifty (single-IC!) circuit to drive the bipolar stepper motor that's a part of floppy drives: __ Designed by Wilf Rigter
NuStepper - Uses just a single IC ('though not one you're likely to have in your "parts box") to give you reversible motor drive __ Designed by Wilf Rigter
Oatley DC Motor Windmill - Based on a 300watt 24v DC scoota motor, this little windmill would work well if I could boost the output voltage.
On/Off Motor Control with Brake - Modern electronic speed controllers (ESCs) are very efficient, but they still have some drawbacks. An inexpensive ESC with two IRFZ40 MOSFETs has an on-resistance of 14 milliOhm. At 20A current, this means a voltage drop of 0.28V, and a power loss of 5.6W. Furthermore, to build an ESC with a brake generally requires an expensive P-channel MOSFET
On/Off Motor Controller with Brake - The circuit for the controller begins with a buffer, consisting of R1, R2, R3, and Z1A, which isolates the receiver from the rest of the circuit and makes operation of the circuit independent of the exact signal levels from the receiver. __ Designed by Stefan Vorketter
One 9V battery gives +18, +25, +33V - This circuit is based on MAX1044 is a charge pump converter __ Designed by R.G. Keen
One component drives stepper Motor - The extremely simple circuit in Fig 1 drives a stepper motor directly from 12V ac , 60 Hz power supply. Usually you need switched-dc voltages to drive a stepper motor. But a stepper motor will run off ac lines if you introduce a 90° phase shift between the voltages applied to the motor's two windings. In this case only one 6.8uF non polarity capacitor is needed. __ Contact: info @ wzmicro.com
One Wire Barometer - OWW is an application for Linux and RISC OS
to drive the 1-wire weather station. . . . Designed by Simon
Melhuish
Op Amp based PID Controller with SPICE simulation - We've all heard about the wonders of the PID controller, bringing a system's output - temperature, velocity, light - to its desired set point quickly and accurately. But now, your boss says okay, design one for us. Although there's a number of ways to do it, the circuit above nicely separates the three terms into three individual op amp circuits.
Op-Amp Current Source with Floating Load including SPICE simulation - The circuit above maintains a current through a floating load RL (neither end is connected to ground.) The key to the circuit's operation is in placing a current sensing resistor RSENSE in the op amp feedback loop. The current delivered to the load RL is: I = Vin / RSENSE How does the circuit work? Three simple functions help this circuit accomplish its goal. (Remember, no current flows into the op amp's input terminals.)
Optically isolated stepper Motor controller - These are some very high-level instructions for building the Opto-Isolated Stepper Motor Controller. Not really a lot to say. Most of the construction is self-explanatory using the PCB artwork, the overlay, and the schematic. Note that the pad for pin 1 on ICs and such are square to help in proper placement. All ICs on the board are NOT oriented the same way, so pay attention. __ Contact: wrb @ cbnews . att.com
Optically Isolated TRIAC Driver - One simple way of isolating the two parts of the circuit is shown below. If a high intensity red led is used in the circuit below, the TRIAC can be switched using a current as low as ½mA. This means that the circuit can be connected directly to the output of an op. amp. or even a CMOS
logic chip. __ Designed by © David Hoult
OptoCoupled Gate Detects Motor Operation - 02/02/98 EDN-Design Ideas - Most applications require redundant system checks to ensure that devices are operating as expected. The circuit in Figure 1 detects when a PWM-controlled servo motor is running. You can monitor the motor-running signal output with a CPU or tie the output to hardware that indicates a fault if the motor is running when it should be off. The motor's output connects to input resistors RIN1 and RIN2. The use of two resistors protects the motor or servo amplifier in the case of a short circuit. RIN1 and RIN2 also serve as current-limiting resistors for the LED in the opto gate, IC2. Design by Malcolm Watts, Wellington Polytechnic, Wellington, New Zealand
Optoelectronic position control simplifies Motor Movements - 29-Apr-04 EDN-Design Ideas - The optoelectronic technique for achieving position control provIdeas an inexpensive, easy- to-design method of achieving simple, repeatable movement using fixed index points with linear- or rotary-motion components. The simple, basic design in Figure 1 for sequential position control exploits the quick response time of a power op amp, working in tandem with a pair of photodiodes Design by Marie Rivera, Apex Microtechnology Corp, Tucson, AZ |
