Power on time delay relay circuit8/2/2023 ![]() I have been teaching electronics for over 40 years and repaired over 35,000 electronic appliances such as TV’s amps, VCR’s etc. I get 6,000 visitors each day and the site is one of the largest electronics sites on the web. In an answer to your emails to me: No I won’t be removing your circuit from my website: Spot the Mistake. I know what little Jack would say when he’d meet you. You could have just been a sport pointing out to improvements instead of immediately going the grudgeful schoolteacher route to put it up for everyone to see how faulty it is, that it is the worst and won’t work at all. I just sketched the circuit up rather fast as an improvement over the utterly crappy circuit on this page. My circuit worked in the first place and only needed a little tweaking, it was even usable in the first place, hence your statements about mistakes are toatlly out of place. Your acting in this thread has only lead to negative thoughts and will only aid in scaring novice designers off posting about their ideas. Also you obviously are a glass half empty kind of person, enjoying to emphasise the negative in others, while denying your own. We send out equipment in to the harshest and most corrosive of environments and for that reason like to use different parts as in your average living room, you obviously haven’t seen much equipement outside that kind of environment.īy your standards discarding this circuit as faulty and mistaken, even at first claiming it would not work at all just indicates your lack of creativity and vision. And I am totally not impressed as I repair far more advanced military and broadcast equipment, and designed far more complex circuitry as this little delay circuit. So you admit you feel bad about this and know you’ve been exaggerating.įor such an experienced person you have made a whole list of faulty assumptions and mistakes, you could include yourself on your spot the mistake page mister. Threats? I just said I would put this discussion up on some international fora, you feel threatened by that because you fear I will do. “and any threats you have made to me, obviously come from someone who is not prepared to learn” ![]() I am experienced enough to know this is also vastly exaggerated, which doesn’t make it a more reliable statement. “This circuit is one of the worst I have seen” “Before putting a circuit on the web as being a “Quality-Design”, you should ask on a forum for advice and improvements.” Totally lacks, powerful words, you get off on that don’t you? “It totally lacks ELECTRONIC ENGINEERING” “The circuit is not an accurate timing circuit.”Īccurate enough, more accurate than a circuit that discharges at start up. It is so much easier to criticise than to have the imagination to design eh? We have a saying here in my coutry which is literally translated:”the best pilots are on the ground”… Or you could say:”the best swimmers are on the dry”… “if the connections to the gates of T1 and T2 are reversed, the discharging components will turn ON for a brief period”Ī brief period eh? I see another time delay i that then, because if they would be connected to discharge at start up as you describe by swapping the gates of the two fets it will keep discharging C3 and the circuit won’t charge at all. “Altering the circuit to the first two FET’s WILL discharge the cap on start-up” You’d be surprised, just one OB truck in a broadcasting company is laced with these. “There is little or no external interest in this circuit” Diode D1 prevents back EMF when T1 switches off. Capacitor C2 keeps the base bias of T1 steady so that relay clicking can be avoided. ![]() Relay remains latched as long as the voltage level in the mains is normal. The relay connected to the collector of T1 energizes and power will be available through the common and Normally Open contacts of the relay. When the voltage in C1 rises above 3.1 volts, zener conducts to trigger T1. The circuit is a zener controlled switch.Ĭapacitor C1 charges through R1 and VR. It gives power to the device only after one to two minutes of delay after the power is switched on. The time delay relay circuit described here is intended for this purpose. If a short delay is provided, such damages can be avoided. The spurious spike in the power supply when power resumes is due to heavy magnetic flux in the distribution transformer in the mains network. Inrush current at power on or power resumes after a power failure can cause unexpected damage in SMPS based power supply of electronic devices. This prevents deleterious effects due to inrush current and spurious spikes at power on. The SMPS based power supply of these modern electronic devices is vulnerable to spikes in the mains line so it gives a time delay of one minute before applying power to the device. Protect your equipments with this tiny 12V time delay relay circuit. ![]()
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