$5 junkbox Circuit Determines Phase Sequence :
04/23/98 EDN-Design Ideas [file contains multiple
circuits - scroll to find this one]
3 Phase Brushless DC Motor Xtal Based Controller:
This crystal based brushless DC motor controller was
specifically designed to work with SKC (Shinano
Kenshi Co.) streaming tape drive motor part #
DR-4312-001. The principle could be applied to just
about any 3 Phase motor using Hall effect sensors.
The heart of the controller is a 2 chip combination
from Unitrode Corporation the UC3633 and the UC3620.
Inverters form three-phase VCO: 08/02/01 EDN
Design Ideas - You sometimes need an inexpensive VCO
that can produce evenly spaced three-phase outputs
over a wide frequency range. You could use tracking
all-phase filters with only one oscillator, but this
technique is difficult to implement and offers
limited range. Other methods, such as using a DSP,
are feasible, but they're complex and expensive....
Level shifting nixes need for dual power supply:
01/06/00 EDN-Design Ideas / The AD736 true-rms-to-dcconverter
is useful for many applications that require precise
calculation of the rms value of a waveform. This
converter can determine the true rms value, the
average rectified value, or the absolute value of a
myriad input wavefo...
Optocoupler simplifies power-line monitoring:
01/10/02 EDN Design Ideas The use of a linear
optocoupler and a capacitor-based power supply
yields a simple, yet precise power-line-monitoring
system. The circuit in Figure 1 converts the 110V-ac
power-line voltage to an ac output voltage centered
at 2.5V, covering 0 to 5V. The circuit isolates the
output signal from the power line. ...
Phase Splitting: Phase splitting means the
creation of a sinusoidal signal like a given one,
but displaced in phase by a certain amount. A
sinusoidal signal repeats a sequence of values as
time passes, and the cycle is divided into 360
electrical degrees or 2π radians, like a circle. A
rotating phasor is a graphic representation of these
changes. The unit phasor exp(jωt) is said to have
phase ωt in degrees or radians, where ω is the
angular frequency 2πf radians per second. For 60 Hz,
the angular frequency is the familar 377 rad/s.
RF transmitter uses AMI encoding: 11/24/99
EDN-Design Ideas / Although alternate-mark-inversion
(AMI) encoding is well-suited for direct-conversion
FM transmission, designers often overlook the
technique. AMI, a three-phase, synchronous-encoding
technique, uses bipolar pulses to represent logic
ones and no signal to...
Self modifying code extends addressing mode:
12/17/98 EDN-Design Ideas / Self-modifying code
extends addressing mode. VHDL procedure dynamically
opens a file . Configure buck converter for boost
operation. Circuit eases three-phase monitoring. PLL
forms simple MSK demodulator. C makes inexpensive
sine-wave generator. 74...
Three phase power supply: The "small" three
phase power supply is capable of delivering 3.5 kV
at 1 A. The 380 V AC is connected via a start-up
circuit, limiting the initial current. It is a
temporary power supply, used until the final one is