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Timers and Counters Circuits,
Page 5a Timers & Counters:
#-AB-EF-LM-S Previous T-Z Last Updated on:
Friday, March 12, 2010 12:07 PM
Links to electronic circuits,
electronic schematics, designs for engineers, hobbyists, students & inventors:
Use a Trick to Count Scope Events: 01/21/99 EDN-Design Ideas /
(added 11/05) One advantage digital storage oscilloscopes (DSOs) have over
analog scopes is trace persistence. You can easily see infrequent waveform
features using a scope in infinite-persistence mode. However, the frequency of
these features relative to that of a "normal" signal can sometimes be less than
obvious. You may wonder, does that glitch appear 10% or only 1% of the time? And
how often does that short clock cycle occur? When you take trace noise into
account, even a color-gradded display does not directly or accurately give the
information. A histogram is the most accurate way to give the information, but it
requires time and expertise. The following hint provides a quick way to determine,
using a DSO, how often each of two waveforms occurs....
Use time domain analysis of Zobel network: 06/27/02 EDN Design Ideas
/ (added 8/03 A Zobel network is useful in making a reactive load
appear as a pure resistance to a driving source prone to stability problems
(Reference 1). A typical situation is an audio power amplifier driving a
loudspeaker, modeled at first approximation as an inductance and a series resistor
(Figure 1a). The addition of a series R2C network in parallel with the series R1L
network forms a Zobel network ......
Using the Power vs Time Curve: MicroNote 104 from Microsem Guides the
reader in determining peak pulse power and peak pulse current for pulse widths of
different values than those specified for a given device. (app note added 6/06)
VCXO makes inexpensive dual clock reference: 11/27/03 EDN Design Ideas
/ (added 1/05) This Design Idea describes an inexpensive circuit to
generate two extremely high-quality, crystal-clock-reference-signals, one of which
is a PWM-controlled VCXO (voltage-controlled crystal oscillator) clock signal
(Figure 1). The design also includes circuitry to statically switch and hold the
VCXO at its nominal fixed frequency of operation (equivalent to 50% PWM) without
requiring any external......
Watchdog Circuit uses AC Triggering: 08/16/01 EDN Design Ideas /
(added 1/05) A dc-triggered reset of a watchdog circuit is prone to failure. If
the watchdog program hangs up, then the reset signal becomes activated continuously,
and the microprocessor has no way to escape the situation. We found that a simple
solution uses an ac trigger to reset the watchdog circuit (Figure 1)....
Watchdog Timer Allows Entry to Test Mode: 07)/19/01 EDN Design Ideas /
(added 1/05) Manuals for microprocessor-based devices often include instructions
for entering a "secret mode" in which you can test or reset the device. These
instructions typically ask you to depress and hold one or two switches for a minimum
time interval. You can adopt several measures to avoid accidentally triggering the
test mode: Depress two keys, hold both keys simultaneously and continuously
through......