# 5 sec delay ON timer .. #2

#### crutschow

Joined Mar 14, 2008
26,811
Will it be operating from a 28Vdc supply?

#### dl324

Joined Mar 30, 2015
12,685
Will it be operating from a 28Vdc supply?
8.5V via the zener diode.

#### dl324

Joined Mar 30, 2015
12,685
I want all values of the components for 3-5sec delay before on circuit
$$T = 1.1R_1C_2$$

#### bertus

Joined Apr 5, 2008
21,258
Hello,

There are 2 times a R5 in the schematic.
One on the base of the first transistor and one in the collector or emitor (depending wich schematic you follow) of the first transistor.
There are also no values for the second R5 and R6.

Bertus

#### crutschow

Joined Mar 14, 2008
26,811
8.5V via the zener diode.
I understand that's what the schematic shows.
I was trying to determine if the TS will be actually operating the circuit at that voltage.

#### Dodgydave

Joined Jun 22, 2012
9,920
10uF and a 470K pot will give you upto 5 Seconds.

#### eetech00

Joined Jun 8, 2013
2,300
please can someone help me with this circuit? I want all values of the components for 3-5sec delay before on circuit

View attachment 221514
Hi

Here is an alternate circuit that operates using 12v zener regulator and 12v relay.
Delay on is adjustable from ~3-5 seconds.

If you want the relay to energize at power on, de-energize after timeout:
remove 12v connection to relay, then connect relay to ground
reverse the diode D1 connections at relay (cathode to "out", anode to ground).

Last edited:

#### sghioto

Joined Dec 31, 2017
2,274
Given the supply voltages as shown this will provide a 3 or 5 sec delay before the relay is activated.