radio schematics

AM Receiver
This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now replaced by the MK484. The design is simple and sensitivity and selectivity of the receiver are good.

Medium Wave Active Antenna
This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover the medium waveband from about 550Khz to 1650Khz. The tuning voltage is supplied via RV2, a 10k potentiometer connected to the 12 Volt power supply.

Q- Multiplying Loop Antenna
This circuit is designed to be used in conjunction with the standard 4 foot square loop used in MW for long distance reception.

ZN414 Portable AM Receiver
An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.

SW Receiver Using ZN414
A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands.

MK484 Radio with Loudspeaker
A complete AM radio set based on the MK484 IC (formerly ZN414). It uses a PNP transistor and can drive a 150R loudspeaker.

Radio Receiver Design
This tutorial will teach you in very easy steps how to design basic radio receivers. I will attempt to de-mystify most aspects of design by my usual extremely casual approach to an electronic tutorial. It doesn't matter whether you are a short wave listener, an A.M. radio dx'er, into hobby electronics or amateur radio design, the broad basic principles will still apply.


Build A One Transistor FM Radio
AM radio circuits and kits abound. Some work quite well. But, look around and you will find virtually no FM radio kits. Certainly, there are no simple FM radio kits. The simple FM radio circuit got lost during the transition from vacuum tubes to transistors. In the late 1950s and early 1960s there were several construction articles on building a simple superregenerative FM radio. After exhaustive research into the early articles and some key assistance from a modern day guru in regenerative circuit design, I have developed this simple radio kit. It is a remarkable circuit. It is sensitive, selective, and has enough audio drive for an earphone. Read more about theory behind this radio on the low-tech FM page.

motor control circuits

Automatic Speed Controller for fans and Coolers

Soft Button type Motor Direction Controller

Discrete component motor direction controller

Super simple stepper motor controller

AC motor control circuits

Push Button Motor Control Circuits

The circuits on this page are for motor controls using Push buttons and would typically be found in commercial and industrial installations.

Brush-DC Servomotor using PIC17C756A
This application note demonstrates the use of a PIC17C756A microcontroller (MCU) in a brush-DC servomotor application. The PIC17CXXX family of micro-controllers makes an excellent choice for cost-effective embedded servomotor control applications. Some of the benefits of the PIC17CXXX MCU family include fast instruction cycle execution (up to 120 ns), an 8 x 8 hardware multiplier, and many useful hardware peripherals.


Microchip’s Fan Speed Controllers to a SPI
Microchip's TC642, TC643, and TC646 are the world's first integrated circuits dedicated for controlling and monitoring fan speed. The new family of fan speed controllers modulate fan speed to compensate for changes in system temperature. This means the fan runs at full speed only when necessary, significantly extending fan life. In addition to increased fan life, fan speed is controlled by PWM control circuitry that is more efficient than conventional linear techniques. The ICs provide other features such as fan current limiting, minimum speed control, auto shutdown, and speed, fault, and over-temperature indication.

DC Motor Speed Control with CMOS ICs
Two low-cost CMOS ICs manage a 12 VDC, current-limited speed control circuit for DC brush motors. The circuit design (see Figure 1) uses PWM (pulse width modulation) to chop the effective input voltage to the motor. Use of CMOS devices gives the benefits of low power, minimal heat and improved longevity. The overall design is simple, inexpensive and reliable, and is useful in applications such as embedded DC motor control where efficiency, economy and performance are essential.


Control 3-Phase AC Motors Using PIC18F4431
This application note describes how the PIC18F4431 may be used to control an ACIM using open and closed-loop V/f control strategies. The application code is built incrementally and demonstrates the following control methods: 1. Voltage-frequency (V/f) control 2. Voltage-frequency control with current feedback 3. Voltage-frequency control with velocity feedback and PID control The PIC18F4431 incorporates a set of innovative peripherals, designed especially for motor control applications. The utility of these peripherals is demonstrated in both open and closed-loop three-phase ACIM motor applications. It is assumed that the reader is already familiar with the theory and nomenclature of AC induction motors. For an excellent introduction to the basic concepts of induction motors control, please refer to Microchip?s application note AN887, ?AC Induction Motor Fundamentals?

Motor Control Sensor Circuits
Sensors are a critical component in a motor control system. They are used to sense the current, position, speed and direction of the rotating motor. Recent advancements in sensor technology have improved the accuracy and reliability of sensors, while reducing the cost. Many sensors are now available that integrate the sensor and signal-conditioning circuitry into a single package.

 AC switching with TRIAC from TTL Schematics wiring diagram circuits
 schema electronic projects.


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AM portable radio receiver by ZN414 IC

AM portable radio receiver by ZN414 IC

Description:


An AM portable radio receiver made from the ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.



Notes:

Designed around the popular ZN414 IC this receiver covers the medium wave band band from approximately 550 to 1600 KHz with the values shown. The coil and tuning capacitor may be taken from an old MW radio to save time. The ZN414 IC, has now been replaced by the MK484. The integrated circuit is a 3 pin, tuned radio frequency circuit, and incorporates several RF stages, automatic gain control and an AM detector. It is easily overloaded and the operating voltage of th IC is somewhat critical to achieve good results.



In this circuit a small voltage regulator is built around the BC108B transistor, four 1N4148 diodes, the 2k7 and 10k preset resistor and the 820R resistor. The 10k pot acts as a selectivity control for the whole receiver, controlling the operating voltage for the ZN414 (or MK484). If you live in an area that is permeated with strong radio signals, then the voltage may need to be decreased. I found optimum performance with a supply of around 1.2 volts.



The audio amplifier is built about an inverting 741 op-amp amplifying circuit. Extra current boost is provided using the BC109C / BC179 complementary transistor pair to drive an 8 ohm loudspeaker. The voltage gain of the complete audio amplifier is around 15. The audio output of the complete receiver is really quite good and free from distortion. I may provide a sound sample later. Click here to see a picture of my prototype. I used a small wooden enclosure and the complete tuning assembly from an old radio.

regulator lm317

regulator lm317

Description:


I constructed this voltage regulator to power my two way mobile radio from the car cigarette lighter circuit. It has many other uses and the voltage can easily be adjusted by the use of a potentiometer. The voltage regulator is an LM317T, and should accept up to about 14 volts without problems. It can handle up to 1 amp, but you WILL need a heatsink on the voltage regulator.

The components :

R1= 270R

R2=2K Cermet or carbon preset potentiometer

C1=100nF

C2=1uF tantalum

LM317T Voltage regulator

Heatsink

PCB board



I also added DC power jacks for input and output on my voltage regulator, a green power LED, and a red over-voltage LED. The over voltage LED uses a zener diode to switch on the LED at a certain preset voltage, this can be varied depending on the voltage of the zener diode, I used a 6.2v zener diode. If you plan to vary the voltage for the different items you power, don't bother adding this feature. If you only plan to use items that run on one voltage, this is a very useful feature and will save plugging in and damaging your valuable (or not so valuable) equipment. You can even add a relay to switch off the power if the over voltage LED turns on, but bear in mind it will have to work from the voltage of the zener diode right up to the input voltage. I couldn't add a relay because I couldn't find any that operated from 6.2-13.8 volts. Anyway, the schematic is shown above, the over voltage and power LED are not included in them because it is assumed that anybody who makes this will understand how to use a zener diode

voltage regulator using zener diode

voltage regulator using zener diode

9V Regulator low current Supply

mini power supply regulator give friends try out again. Be fixed voltage regulator 9V size. It uses transistor be pillar equipment perform boost up current tallly go up about 300mA. And by have Zener Diode perform steady voltage at 9Vdc. The detail is other a friend sees in the circuit please yes



http://www.elecfree.com/electronic/9v-regulator-low-current-supply/

Simple Intercom Circuit diagram

Simple Intercom Circuit diagram

This is a intercom circuit diagram.you can use this for your office or for your working place.Acoording to the changes of s1a and s1b You can use this as the reciever and the mic

 

Note

 Use screen wires Between these two circuits

FM Radio Jammer circuit diagram

FM Radio Jammer circuit diagram

This is FM radio jammer circuit diagram.This is not legal device in many countries.So dont misuse this.we dont get any response of it.

 

Note :

 This circuit operates with 9V

 L1 make 6 turns of 16AWG enamelled copper wire on a 9mm plastic former.