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Saturday, September 21, 2019

Electronics Club - John Hewes

A website for anyone wishing to learn about electronics or build simple projects. Written for beginners but used by many others as a quick reference.

Example Projects, Construction of Projects, Soldering Guide, Study Electronics, Electronic Components, 555 Timer and Circuit Symbols.

Electronics Club - John Hewes

This is good place to start your electronics study, it has a practical and simple Approach - delabs

Electronics Club - John Hewes

Starter kit of parts

If you are new to electronics and would like to try adapting published projects, or designing and building your own circuits, you need to have a small stock of components available.

Ozitronics - Electronic Kits

"Audio Amplifiers, Voice Recorders Clocks, Counters & Timers, Data Acquisition & Control Educational Kits, Test & Measurement "

Ozitronics - Electronic Kits

K1001 - 8 Channel Serial Servo Controller, Assembled & Tested

Ozitronics - Electronic Kits

K1001 is an 8-Channel Serial Servo Controller based on the Atmel 89C2051 microcontroller. It accepts RS232 or TTL serial data from a computer or microcontroller and outputs PWM (pulse width modulated) signals to control up to eight RC servo motors (as used in radio-controlled model airplanes, cars, etc.).

Unused servo pins can be reconfigured for digital output to drive on/off devices.
Up to four controllers can be multi-dropped on a single serial port for controlling up to 32 servo motors - more on request.

Sunday, September 15, 2019

555 based Reset Generator

You must have read all the circuits and explanation on the other pages at delabs to understand this, as i cannot repeat the same thing as i have done it more than once already.

The circuit is a 555 monostable, The push-switch is to trigger and generate a reset pulse for uC. The diode is for OR' ing later. The High will go thru the diode but the Low of 555 cannot drink any current as diode blocks.

555 based Reset Generator

The bottom part of the Circuit is the CD4093 Schmitt nand based flipflop. This is my favorite because of studying designs in Elektor Electronics.

What is the Schmitt then ?, It is better to visit the links below to learn. It can make a sine or triangle or any shape waveform to square. It can help square a very messy waveform.

Digital Timers Counters and Clocks

Two nand gates are connected to form a flip-flop toggle switch. When 555 gives out a pulse, the pulse is delayed by a R-C which results in a ramp, the third nand-Schmitt gives out delayed low trigger to toggle nand-flipflop-switch. The Nand-toggle-switch is rest at any time with the lower pushbutton. The fourth nand output gate is not really required. But the 4093 is quad nand, so unused nand inputs should not float , pull-up or pull-down. So it has just been added in circuit so that he can fit some role, or else he will be bored.