This circuit turns-off an amplifier or any other device when a low level audio signal fed to its input is absent for 15 minutes at least. Pushing P1 the device is switched-on feeding any appliance connected to SK1. Input audio signal is boosted and squared....

Here`s an antenna selector, Preselector, attenuator, preamplifier accessory for every HF amateur transceiver. It can improve your receiver`s IP2 for out-of-band signals and yield good flexibility. My father, I4FAF (an old-timer) and I both very much like....

The designer of this circuit had fitted two (waterproof) loudspeakers in his bathroom and connected them to the stereo system in the living room via a long cable. Naturally, this promptly led to the desire to be able to use the remote control unit from the....

The cumulative timer circuit consists of resistor R1 and spreadsheet internal crystal oscillator BC, and it is shown as the chart. R1 and R2 choose the metal film resistors: R3 ~ R5 select the 1/8W metal film resistors. C select the aluminum electrolytic....

A very long time constant is provided by R1 and C1. C1 discharges and the near zero voltage at its positive lead is applied to the high impedance inputs of the....

Provides timing in seconds to 99 s, and timing in minutes to 99 min, with 2-digit LED indicator showing elapsed time. Desired interval is set with BCD thumbwheel switches. LED readout counts up to preset time, then resets automatically to zero. Switch giving....

ECEN 2250 myDAQ Experiment Capacitors and the 555 Timer...

sections you can follow in this datasheet applications are general design consideration of the 555 timer, frequently asked applications question (FAQ), design formulas, and sample of some ingenious applications. The sample of applications were presented such....

This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input devices - such as magnetic-reed contacts, foil tape and PIRs. If you wish - you can use a mains....

The regulated output voltage varied as the unregulated DC voltage changed, and that changed as the load current or the incoming AC line voltage was varied. There was no easy fix to the existing circuit that would solve this problem. Eric WB6FLY had already....

a programmable clock timer circuit that uses individual LEDs to indicate hours and minutes. 12 LEDs can be arranged in a circle to represent the 12 hours of a clock face and an additional 12 LEDs can be arranged in an outer circle to indicate 5 minute....

Simple to build, simple to make, nothing too complicated here. However you must use the CMOS type 555 timer designated the 7555, a normal 555 timer will not work here due to the resistor values. Also a low leakage type capacitor must be used for C1, and I....

The Clock Controller was designed to be an exemplary of using `C` language to control timer0 interrupt, 7-segment LED and keypad scanning. It provides 1-bit sink current driving output, for driving a relay, opto-triac, say. Many projects requiring 7-segment....

A PIR sensor is triggered by itself when using a timer to wait 2 seconds after the sensor is triggered. Without using the timer to wait the sensor works as expected. I have a PIR sensor connected to an ATMega328p. The PIR sensor has three pins; VCC, GND and....

Timer Garage Door Circuit schematic diagram, printed circuit board..

No matter WHAT the label on the radio (or the seller) says, no Spectra will ever operate over the entire 136-174MHz (high band) or 403-512MHz (UHF) frequency range. Each unit will do only a portion of that band`s frequency spread, and that portion is called....

A rectangular-wave pulse generator with an extremely long period can be built using only two components: a National Semiconductor LM3710 supervisor IC and a 100-nF capacitor to eliminate noise spikes. This circuit utilises the watchdog and reset timers in....

An Infra Red wired Repeater circuit to control appliances from a remote location. Parts List: R1: 1k Resistor (1) R2: 3.3k Resistor (1) R3: 10k...

..

Hi i am ajinkya this is my first Instructable -SIMPLE WATER DETECTOR For this project u will need the following parts: 1.IC 555 timer-1 2.Small size g....

This circuit is a compact timer circuit that will keep the headlights of your car ON for about 1. 5 minutes and then turns it OFF. This circuit incorporated to your car will help you to access dark places with out the need to come back and turn OFF the head....

and Flash Memory schematic that can be done from the following sources: power-on reset, external reset, software reset, watchdog timer reset, and brownout reset. The figure (click to enlarge) shows a recommended external reset circuit for the MSC1210 with....

This circuit will transmit a continuous audio tone on the FM broadcast band (88-108 MHz) which could used for remote control or security purposes. Circuit draws about 30 mA from a 6-9 volt battery and can be received to about 100 yards. A 555 timer is used....

used to maintain a deep cycle battery from a solar panel. This is a combination digital clock timer and solar panel charge controller. Component: ....

This article provides conversion instructions for radio model # GE/MACOM MASTR-III Group 2 (150. 8-174 MHz) Repeater or Base, Combination Number SXS, to allow it to perform adequately in the 144-148 MHz range. Please be aware that this document is currently....

The following is a layout of my repeater system and what was needed to get it on the air. The ILink system was designed by Graeme, M0CSH, and I take no credit for its success. The circuit below is only required by repeater control stations (sysops) and not....

..

This random timer circuit is based on a Atmel ATTINY24 avr driving one power relay. You can use this circuit to switch on and off other circuits randomly. For example, when using this circuit on a model railroad you can turn on and off parts of the animated....

This circuit diagram shows how to obtain a negative voltage from a positive voltage supply. Another advantage of this circuit is that, the negative voltage together with the original positive supply can be used to simulate a dual supply. The circuit is based....

Here is a simple project using very common electronics components for charging mobile battery using AA cells. The main part of the circuit mobile cellphone charger is timer IC NE555, used to charge and monitor the voltage level. IC1 get control voltage to....

Those of you who own large 500 watt and higher Astron linear power supplies, and even large HF amplifiers, know all too well that "GNNNNnng" sound that they often make when turned on. This is due to the high inrush (surge) current flowing into the....

3V Battery powered, Beeps after a fixed minutes delay This circuit was developed since a number of visitors of this website requested a timer capable of e....