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Delay Circuits
Delay Circuits:  #'s - Q     R - Z


Last Updated: November 22, 2021 02:41 PM

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
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Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

Relay Delay -  This circuit waits for a set time and then activates a relay.  With the cap that is in the schematic you will get about a 6 sec delay till power on.  You can change the cap in this circuit to 470uF for about a 20 sec delay __

Relay: Delayed Turn-on -  This circuit is a delayed turn-on relay driver and can produce time delays for up to several minutes with reasonable accuracy.  The 14001 (or 4001) CMOS gate here is configured as a simple digital inverter.  Its output is fed to the base of a regular 2N3906 (PNP) transistor, Q1, at the junction.   __ Designed by Tony van Roon  VA3AVR

Relay-12 Sec to 90 min -  Schematic and notes only, no circuit description provided.   __ Designed by Tony van Roon  VA3AVR

Smooth Tone Clickless CW SideTone Generator -  This circuit is about as good as it gets for generating morse code tones.  It may be used as a code practice oscillator, a tone generator for a keyer, a sidetone oscillator for a CW transmitter or an audio Modulated CW (MCW) generator for an FM transmitter or repeater __ Designed by G. Forrest Cook

Soft-Start for Power Amps -  Although the soft start circuit can be added to any sized transformer, the winding resistance of 300VA and smaller transformers is generally sufficient to prevent a massive surge current.  Use of a soft start circuit is definitely recommended for 500VA and larger transformers __ Designed by Rod Elliott  ESP

The SportSync Audio Delay Module -  Many sports fans feel that radio commentary is better than that on TV, particularly commercial TV.  To eliminate the annoyance of the TV commentary (and the adverts) they want to turn down the sound on the TV and listen to the radio instead. ___ SiliconChip

Time Delay Generator -  Circuit Ideas for Designers App Note___ Advanced Linear Devices, Inc

Time Delay Relay -  A time delay relay is a relay that stays on for a certain amount of time once activated.  This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay.  The time is adjustable from 0 to about 20 seconds with the parts specified.  The current capacity of the circuit is only limited by what kind of relay you decide to use __ Designed by Aaron Cake

Time Delay Relay II -  When activated by pressing a button, this time delay relay will activate a load after a specified amount of time.  This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor.  The current capacity of the circuit is only limited by what kind of relay you decide to use __ Designed by Aaron Cake

Time Delay Relay-Power OFF -  The two circuits below illustrate opening a relay contact a short time after the ignition or ligh switch is turned off.  The capacitor is charged and the relay is closed when the voltage at the diode anode rises to +12 volts.  The circuit on the left is a common collector or emitter follower and has the advantage of one less part since a resistor is not needed in series with the transistor base.  However the voltage across the relay coil will be two diode drops less than the supply voltage, or about 11 volts for a 12.5 volt input. __ Designed by Bill Bowden

Time Delay Relay-Power ON -  Here's a power-on time delay relay circuit that takes advantage of the emitter/base breakdown voltage of an ordinary bi-polar transistor.  The reverse connected emitter/base junction of a 2N3904 transistor is used as an 8 volt zener diode which creates a higher turn-on voltage for the Darlington connected transistor pair.  Most any bi-polar transistor may be used, but the zener voltage will vary from about 6 to 9 volts depending on the particular transistor used.  Time delay is roughly 7 seconds using a 47K resistor and 100uF capacitor and can be reduced by reducing the R or C values. __ Designed by Bill Bowden

Time Relay12 Sec to 90 min -  Schematic and notes only, no circuit description provided.   __ Designed by Tony van Roon  VA3AVR

Time-delay relay reduces inrush current -  03/07/02 EDN-Design Ideas A transformer switching onto a line can sometimes cause a circuit breaker to trip or a fuse to blow.  This phenomenon occurs even if the transformer presents no load, such as when the secondary is open.  The problem arises because of the heavy magnetizing inrush current in the transformer.  The amplitude of the current depends on the instant on the ac waveform at which the transformer become__ Circuit Design by P Seshanna, Assumption University, Bangkok, Thailand

Timers for Very Long Delays using a CD4 541B -  Very Useful Timers __ Designed by G.L. Chemelec

Transistors offer overload Delay -  16-Sep-04 EDN-Design Ideas Although an SMPS(switch-mode power supply] can protect itself against permanent short circuits, it sometimes has problems when dealing with transient overloads.  Transient overloads are not short circuits but can push the power supply above its nominal load value.  This scenario occurs with typical loads such as printer heads and small motors__ Circuit Design by Christophe Basso, On Semiconductor, Toulouse, France

Windshield Wiper Delay -  The intermittent wiper circuit shown above causes the auto's windshield wipers to wipe once every several seconds instead of constantly wiping.  The circuit may be added to older cars to provide the intermittent function or it __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Delay Circuits:  #'s - Q     R - Z

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