ON off delay circuit to drive relay

Thread Starter

Avinash B P

Joined Mar 2, 2022
10
Hello

I need to develop a 100ms delay circuit to energize / de energize the relay. Could any one help me. Relay coil voltage 12V. And relay coil state is controlled by comparator having 0 to 15 level transition.
 

dl324

Joined Mar 30, 2015
14,458
Your objective is unclear to me.

  1. What event initiates the 100ms delay?
  2. How long do you want the relay to be energized?
  3. If the relay is operating from 12V, does that imply that the rest of the circuit also operates from that voltage?
  4. What do you mean by 0 to 15 level transition? What is your definition of level?
  5. What is the comparator comparing and what is it to control?
 

ci139

Joined Jul 11, 2016
1,815
LM311 , NE555 , LMC555 or LTC6994 or alike . . . also a transistors based Schmitt trigger with suitable delay network at it's input
. . . depending on the allowed tolerance for the 10ms . . . a digital precision timer
where the outputs of the first two can effortlessly drive the relay while the rest likely will need more parts to form the circuit
 
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Thread Starter

Avinash B P

Joined Mar 2, 2022
10
The high voltage is measured by the sensor and when It increases above the threshold during more than 100ms, the relay is driven. When relay is driven, the high voltage is still measured, if it decreases below the threshold during more than 100ms, the relay is released.
 

ci139

Joined Jul 11, 2016
1,815
during more than 100ms, the relay is released.
does that mean that
  • when the HV drops below the threshold within the 100ms - the relay stays deployed -e.g.- an additional memory element is required
  • when the HV drops below the threshold within the 100ms - the relay stays deployed for this 100ms only . . . if not SCR - the relay may have several tens of ms to respond
!! or !!
increases above the threshold during more than 100ms
does this condition disables the relay to respond altogether if the threshold-pass event has a duration less-equal to the 100ms (will also require a memory elm. or additional "logic" / circuit modding)
 
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