This circuit is a RF modulator which can be used for modulating of video signals. The P1 controls the Light and the P2 controls the contrast of video signal. The RF modulated output signal can be received on the VHF band ( about 189 MHz ). Note that the circuit don’t modulate the audio signal [...]
This circuit gives out an alarm when its sensor is wetted by water.
A 555 astable multivibrator is used here which gives a tone of about 1kHz upon detecting water.
The sensor when wetted by water completes the circuit and makes the 555 oscillate at about 1kHz.
The sensor is also shown in the circuit diagram.
It has to [...]
This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold. The circuit operates as follows: The RED wire from the phone jack is typically positive and the GREEN wire is negative or ground. When you want to place [...]
All resistors are 1/4W.The circuit is powered by 9…15V DC or AC. When In Circuit Programming (ISP) connectors are used, is possible the programmer to be powered from target’s power source. Diodes D2 and D6 protect the regulator LM7805, when target’s power is used.
‘ XTAL JUMP ‘ is used to cut XTAL when the AVR [...]
Circuit High power supply regulater 0-30V 20A by LM338
This is High current and Adjustable Volt 0 to 30V 20A.
It easy circuit and nice circuit, Because use IC LM338 and IC 741.
Volt Output adj by VR1-1K.
IC LM338 to hold heat-sink. Transformer is 20A up.
Componets
R1 = 180 KOhm C1, 6 = 10uF/16V TR1, 2, 3 = BC547 , BC548
R2 = 12 KOhm C2 = 47uF/16V P1 = 10 KOhm trimmer
R3, 8 = 47 KOhm C3 = 4,7 pF P2 = 47 KOhm trimmer
R4 = 3,9 KOhm C4, 7 = 1 nF IC1, 2 = 741 OP-AMP
R5, 6, [...]
This project allows instant start sequentially but a dozen low-voltage lamps 12 V / 60 W, and makes them fade and always sequentially (but slower). This system has been designed to meet the demand of a visitor who wanted ten recessed low voltage spot in a driveway to his house, with the following function: – [...]
This circuit allows switching on a LED when the battery voltage (12V) drops below a certain threshold. The operating system is based on a comparison of tension, which comes in a zener diode. If the supply voltage is 12V and the zener diode is a 10V model (this is the case in the diagram), we [...]
This is a good looking and practical device that can be useful in many areas where countdown timer is needed. This project is based on the PIC16F84A microcontroller. The time range can be adjusted between 1 and 999 seconds. This project has 3 buttons and one of them is named Set Button. In order to [...]
A VU meter is often included in audio equipment to display a signal level in Volume Units; the device is sometimes also called volume indicator (VI). In this project we are building a basic and low cost LED VU Metre circuit . The extent (range) display is -18 dBu to +3 dBu, spread over [...]
Today we have a new category “Projects” and a new electronic project 12 Channel LED Chaser with PIC16F84A.
This project is based on the popular PIC16f84A micro-controller.The heart of this project LED chaser is the PIC16F84A PIC microcontroller.A 4MHz crystal and capacitors C1 and C2 22pf is used for providing clock pulses to the micro-controller. The [...]
