That original HiFi-amplifier loudspeaker protection may delay about 2 seconds.
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BTW: Tried a linear regualtor IC 78H05SC and reduced the output electrolytic capacitor value from 470 µF to 47 µF => and starting power on self reset works as desired.
Tried some NE555- circuits. However those ones triggered with a short glitch directly on Mains power on. This was not intended, basically.
Now working with delay circuit for proper start posted below in attachment. Transistors BC 337-16. Relay OMRON G5L-117p-ps 5V. Cover can be dismantled for contact cleaning purposes (if necessary).
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The delay time is on first start after a longer period of "power off" approximately 5 seconds. If power switched "off" and directly consecutively again "on", delay time is at least 1 second. Reason: C1 will be discharged over BE-path of Q1, mainly. And then only from approx. 0.4V towards 0.7V and not 0V to 0.7V charging. All transistors are saturated, show UEC approx. 0,1V. Current 1.3 mA on start, 70 mA in state "on" according current via relay's coil. In order to make switching off contacts a liitle bit faster, the Zener diode D2 added antiserial to D1, together resulting only approx. 4V in "negative" direction.
Comments
Linear versus switch-mode is an ongoing quest and debate.
I have tried both over the years on the Kiwi and other SDR
I have found these to be quiet and with a DIN rail, easily mounted
Other users have used Meanwell in other chassis types.
https://www.amazon.com/MDR-60-5-meanwell-Industrial-Supply-MDR-60/dp/B01N58K3S4
That original HiFi-amplifier loudspeaker protection may delay about 2 seconds.
BTW: Tried a linear regualtor IC 78H05SC and reduced the output electrolytic capacitor value from 470 µF to 47 µF => and starting power on self reset works as desired.
My realization all entrusted ... it seems to be fine. Classic power supply, trafo+78h05 ..
Tried some NE555- circuits. However those ones triggered with a short glitch directly on Mains power on. This was not intended, basically.
Now working with delay circuit for proper start posted below in attachment. Transistors BC 337-16. Relay OMRON G5L-117p-ps 5V. Cover can be dismantled for contact cleaning purposes (if necessary).
The delay time is on first start after a longer period of "power off" approximately 5 seconds. If power switched "off" and directly consecutively again "on", delay time is at least 1 second. Reason: C1 will be discharged over BE-path of Q1, mainly. And then only from approx. 0.4V towards 0.7V and not 0V to 0.7V charging. All transistors are saturated, show UEC approx. 0,1V. Current 1.3 mA on start, 70 mA in state "on" according current via relay's coil. In order to make switching off contacts a liitle bit faster, the Zener diode D2 added antiserial to D1, together resulting only approx. 4V in "negative" direction.