Clock Circuits

What is the effect of crosstalk from the digital data signals into the clock signal of a data-conversion system? This is a more obscure problem than crosstalk from digital bits into the analog signal path, which was the subject discussed in the previous article: Part 1 of this series, Effects of Digital Crosstalk in Data Converters...

The Multimeter Clock consists of three multimeters, the first meter displays hours, the second displays minutes and the last displays seconds. A 16F628A PIC microcontroller keeps track of time and outputs a calculated current to each meter to display the current time. The user enters the time by pressing three time adjust buttons. The first button increments the hours, the second button increments the minutes and the third button resets the seconds. Once the time has been.....

Many systems use watch-crystal-based, 32.768-kHz oscillators. In battery-powered designs, the 32-kHz oscillator may consume a fairly high percentage of the total power budget. Reduced power consumption equates to longer battery life, smaller batteries, and smaller products...

Today`s digital delay lines can process pulses no shorter than their delay times, and that restriction confines the devices to applications in which the duty cycle remains near 50%. A limited range of available delays (2 to 100 nsec per tap) further limits their use. Longer delay is available with one-shot multivibrators of standard digital-logic families, but those devices do not retain duty-cycle information...

Designed for monitoring charge and discharge current in secondary batteries, IC1 outputs a current of 0.5 mA per amp of load current flowing through its internal sense resistor while rejecting common-mode supply-voltage noise. The on-chip sense resistor handles as much as 3A of continuous current...

This circuit provides a digital square wave that can be viewed directly or used to drive other circuits. It used the CMOS 4047 Low-Power Monostable/Astable Multivibrator. As used in Tom Duncan's Adventures with Digital Electronic's Book, to drive CMOS Decade of 4-bit binary counters...

This was my second Nixie clock project. I wanted something a little smaller / cheaper / simpler then my rather large B-7971 clock. I will post the design for that one of these days. I was trying to simplify everything. And basically wound up with a one chip solution, ... the micro itself does just about everything. The Nixie tubes are relatively cheap and available (Ebay) Russian IN-17s. Discrete transistors drive the tubes in a 1x4 mux arrangement. Needs 15 I/O lines from.....

Because of the nixie-tube is a gas tube, it requires relatively high-voltage supply. Judging from archives, from 180 to 300 volts are used for supply voltage. In this project, 270 volts from rectified 100V line voltage directly is used. It is very simple but whole of the circuit is not insurated from the power line, never touch any part of the circuit...

(Almost) Trivial application of an AT90S2313 or ATtiny2313 in an alarm clock to change the alarm from "BEEP BEEP BEEP BEEP BEEP BEEP BEEP BEEP..." to "WAKE UP" in Morse code. This was designed in response to a request and is in daily use. An inexpensive alarm clock was modified by installing a small circuit board inside the clock body and attaching some wires to the clock's circuit board. The second AA cell needed to bring the voltage up to 3 volts for the micro controller.....