Delay Circuits

Delay Switch

This switch allows the model train at such a station will automatically slow down. The train stands for a certain amount of time and then slowly pulls back. You do not own the train to stop. The relatively simple circuit works. P1 potentiometer for setting the waiting time, while turning to A caused a shorter waiting time and turn to B results in a longer waiting period. P2 is to set the brake and acceleratieweg. Here, too, turn to A results in faster acceleration and the train slows. ..

Delay switching for power amplifiers

This delay can be used in power amplifiers, to prevent the fuses fail when the amplifier is turned on. The circuit is very simple with a relay which turned on when C2 and C3 are charged. If the relay has not been applied, the resistors used to control connected to feed. If after some time the relay attracts the bridge resistors. Watch out for your own safety when building this circuit. On the whole circuit is power. F1 should be the value of having the fuse that normally would be used...

Mains variable Delay circuit

The circuit shown will switch on and off a resistive or inductive load up to 800VA with the possibility to adjust both the on and off period. Switching takes place during the zero crossing of the sine wave. The switch on point is around the zero crossing but pinpoint accuracy is not guaranteed due to the analogue nature of the circuit. The on period is adjustable between 0.3 to 4sec while the off period is adjustable between 0.2 and 10sec. ..

Timer switch circuit

A 100 second delayed turn ON relay RL1 switch, if plug power +12V in circuit. In Fig.2 see a two range 6-60 second and 1-10 minute auto turn off relay timer circuit, with 555...

Analogue / Digital Logger I

Intermittent failures in electronic systems are some of most difficult to diagnose. This device is designed to run for days at a time looking for a failure and logging the event. The unit is based on a PIC16F84. Six digital data lines are brought in via a 74hc165 shift regiser. The shift register is connected to a set of series resistors so that any voltage from about 3 volts to about 30 volts will read as a high condition. A single analog line is read using an ADC8031. (Note: with todays PICs, it would be better to use one with the A/D built in). Once activated, the unit counts off time down to 1/100 second. Any change of state of the 6 digital lines causes it to store the time, the state of the six lines and one analog voltage. ..

Analogue / Digital Logger II

This is a circuit monitoring device. It runs for over 10 days and can log up to 32k events both digital and analog. Samples are logged either on a timing basis (.01 to 2.5 seconds), or on a triggered basis. Four inputs are provided, up to three of which can be analog. All setup and configuration is done via a terminal program. Once configured, the device can run stand-alone monitoring a circuit. The device can then be connected back to a terminal program for data retrieval...

Delay circuit with NE555 timer

This circuit design was used to switch on device via a LED photocell arrangement (optocoupler) using components R1, C1, D1 and Q1. It produces a delay on powering up to ensure correct sequencing of certain equipment. A very simple delay timer using a single transistor and an R-C timing circuit...

This software functions as a long period astable mutivibrator. The mark and space period can be set from 1 second up to a maximum 65535 seconds (18h12m15s). Using the internal 4Mhz RC oscillator delays with an accuracy of 99% or better can be achieved The code also implements an edge triggered reset and an active low hold function. The reset edge can be configured for rising or falling edge. The hold function is active low and stretches the timed period for as long as the hold input is held low. In addition to this up to 128 mark/space time pairs can be used which are executed sequentially allowing complex pulse trains to be generated...

A rising edge on the Trigger input starts a delay timer. At the end of the delay period Output 1 goes high and a second delay timer is started. At the end of the second delay Output 2 goes high. This is repeated for Outputs 3 and 4. The result is four outputs that go high in sequence with user defined delays between each one. Once Output 4 has gone high, a high level on the Reset input causes all four outputs to clear and the program goes back to the initial state waiting for a rising edge on the trigger input...

The purpose of this circuit is to power a lamp or other appliance for a given time (30 minutes in this case), and then to turn it off. It is useful when reading at bed by night, turning off the bedside lamp automatically in case the reader falls asleep... 30 minutes operation Blinking LED signals 6 last minutes before turn-off..

This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types ...

The Saver V5.0 runs simple clock emulation program, turns a night light on and off with preset time, say 19:00 to 22:00 everyday. The design features low cost, easy installation, no battery backup and no EMI. The AT89C2051 uses external oscillator generated by schmitt trigger gate CD4093, ~680kHz. Reference frequency was derived from 50Hz main line...

The Sallen-Key realization of a 5.25-MHz, three-pole Butterworth filter has a gain of 2V/V and can drive 75 back-terminated coax with an overall gain of 1 (Figure 1). Used to reconstruct component-video (Y, Pb, Pr) and RGB signals, this filter has an insertion loss greater than 20 db at 13.5 MHz and greater than 40 db at 27 MHz (Figure 2). Like the antialiasing filter before an ADC, this filter removes the higher frequency replicas of a signal following a DAC. To preserve quality in the video waveform, you should minimize group-delay variations in the filter and any group-delay differential between filters...

Many designers use small pulse generators to delay signals, open timing windows, drive sample/hold circuits, and other functions. Though the hardware implementation of these generators does not pose any problems, the lack of dedicated circuitry sometimes puzzles the Spice simulation of the system. A common approach to this problem is to implement a time constant involving a resistor, a capacitor, and a comparator. Unfortunately, each time you need a time constant, you must recalculate the resistor value, the capacitor value, or both...

Generating complementary clock signals in a Spice simulation is an easy task. However, this task gets much harder if you need to introduce some dead time into the signals. This difficulty is especially true when you`re dealing with a variable-pulse-width-modulated switching cycle. In fact, you need to insert a dead-time interval between the switching of any two power devices in series, such as bridge or half-bridge designs that use MOSFETs and switch-mode power supplies and that implement synchronous rectification...