Circuits (Page 2)

Circuits and Schematics, pdf, png.

Here are circuits made of Resistors, Capacitors and Inductors which are passive components. Crystals, Thermistors, Varistors, Variable Passive RLC are also Passive Parts.

Circuits using only discrete devices

Zeners, Diodes, NPN-PNP Transistors, FET, MOSFET, SCR, Triacs are all discrete active devices. ICs and Hybrid Modules are made of many discrete and passive components. In the Integrated Circuits or ASICs, all parts even passives are derived on the Silicon Wafer. In Hybrid Modules the construction uses SMD or Tiny Chip components interconnected in a small ceramic PCB and Hermetically Sealed if needed.

Parts or Components in Electronics

Parts like Switches, Connectors, Relays and PCBs are ElectroMechanical parts. Nuts, Bolts, Screws, Cabinets and enclosures are Mechanical parts.

For a Systems Integrator or Control Panel Designer, the Timers, Controllers, PLC which are Electronic Products become Components or Modules along with Contacters, Current Transformers, AC-DC Drives etc.

I have updated some pages, and integrated new pages with some explanations. These are related to mains power and power electronics. – ananth

Tables related to Power Electronics

Mains Voltage and Power Circuits

Discrete devices – circuits

Electrical Engineering encompasses Everything in Electronics. Communications, Computers etc. are further specializations of Electronics. So it is best to Identify Electrical Circuits with Electrical Designs which excludes Active Devices. It can include Electronic Products in the form of wireable modules.

So House and Factory wiring, Appliances like Ovens, Toasters, Power Generation and management; all these are electrical. Motors, Generators, Connectors, Relays, Contacters and Circuit Breakers are Electrical Components.

See a diagram i made for a Sequential Process Control Unit, custom built for Vacuum Impregnation;

Sequential Process Control - Vacuum Impregnation

A Radio or Power Inverter is Electronic. When an Inverter or Electronic AC-DC Motor Drive is used in a Control panel or Power Supply system, that integration is shown as an Electrical Circuit. I feel Simple Consumer Electronic Circuits using Diodes, Transistors, SCR, Capacitors and Resistors can also be taken under electrical circuits; when they are used in Mains-Power or Household Appliances. Solar Energy related circuits also can be studied under Electrical Power Circuits.

In Electronics RF-Microwave and Communications is a specialization area, Computer Hardware, Software, Internet form another major domain. Networking and Wireless data communication overlaps both the above.

Power Electronics and Instrumentation are fundamental domains needed for many. Industrial Automation with Process Control Instrumentation is unique, but is supported by the fundamental domains. Many more finer areas like Robotics and Medical Electronics have a much sharper focus.

Basic Electrical Circuits – delabs

Anantha Narayan

This was a Student Project of mine, it is a very basic instruments that could do most of the tasks on a test bench.

The cabinet used, was available as a part of a Hi-Fi DIY System, The Range and Mode switches were Modular Stackable Interlocked MultiPole Switches. The rest of the Interface were wirewound pots, jacks, sockets and plugs. The front panel was Engraved Acrylic, the panel was the toughest issue we tackled.

I wanted it to look well engineered, at least on the outside. It was a total analog instrument except for the digital indication of ICL7107. Thanks to ‘Intersil Hot Ideas’ Applications Book.

The above belong to an instrument Measureall shown below.

MeasureAll Benchtop Instrument

The Incredible and Versatile 555 :

These are some 555 circuits, The most versatile and simple chip of all time !. Some 555 circuits with source in the Cadsoft Eagle format are also here for editing and learning.

555 Timer based Circuits

The best part of the 555 is that it has an voltage detection. It has a Versatile Logic which is defined by voltage comparators. The ability to loop it like an opamp for feedback makes it the first “Programmable” Mixed Chip. In short it make an ideal building block.
Its drive is amazing, it can power small solenoids, lamps and relays. It is a Symmetrical output drive, means Source – push the pectrons into a node and Sink – pull the pectrons from a node. Conventional current is opposite to the flow of electrons. Current flows from positive to negative, so let me use a new word pectron, imaginary ‘+’ electrons, not Positrons.

555 trigger mode cartoon

Tutor Gadgets for 555


Signetics made the 555, This is one IC that is like a E-LEGO, this along with Op-Amps and other components can make many interesting projects. On some pins like Control Voltage it responds to analog signals and on Reset and Output the signals are Digital like. The 7555 a CMOS version consumes lower power and oscillates at higher frequencies.

NE555 Applications and Specifications

“Study .. Learn .. Examine.. Experiment .. Analyze .. Establish .. Realize” Soldermans Basic Electronics

– Solderman 1658

The LM3914 is a monolithic integrated circuit that senses analog voltage levels and drives 10 LEDs, providing a linear analog display. A single pin changes the display from a moving dot to a bar graph. Current drive to the LEDs is regulated and programmable, eliminating the need for resistors. This feature is one that allows operation of the whole system from less than 3V.

LM3914 – Versatile and Easy use Display

  • Drives LEDs, LCDs or vacuum fluorescents
  • Bar or dot display mode externally selectable by user
  • Expandable to displays of 100 steps
  • Internal voltage reference from 1.2V to 12V
  • Operates with single supply of less than 3V
  • LED driver outputs are current regulated, open-collectors

The circuit contains its own adjustable reference and accurate 10-step voltage divider. The low-bias-current input buffer accepts signals down to ground, or V, yet needs no protection against inputs of 35V above or below ground. The buffer drives 10 individual comparators referenced to the precision divider. Indication non-linearity can thus be held typically to ½%, even over a wide temperature range.

My LM3914 Circuits

Millivolt Meter using a LM3914 LED Dot Display
Millivolt Meter using a LM3914 LED Dot Display

The Security Guard duty monitor below, shown in eight circuits at Digital Circuits – 1 are examples of logic circuits, i have converted them from the DOS Orcad to Orcad 9 and corrected some errors a few years back.

Electronic Shift Monitor - delabs

These circuits can be used for looking at the logic blocks or to learn. This product was built and sold to some firms many years back. Now these designs are best done with a PIC or Atmel chip. Here is the user manual

Electronic Shift Monitor ESM9000

This circuit was done with CMOS CD40xx type of ICs. A RAM was used to store the Day/Time LED Status.

This was custom made for a bank, it was to monitor the Alertness of the Security Guard. Periodically the Unit will Buzz and Flash and the Security Guard has to press a Big Button to indicate he is awake, alert, agile and around the Unit.

In the Morning the Bank Manager will see the Security Status LEDs. All Green means fine, few Red LEDs means the Guard was sleeping or gone away from some times. All Red means Security Guard is missing. :-)

Made quite some numbers but was not profitable and soon similar lower cost clones appeared.