overheating

Hi everyone, when i power up the circuits even i don't trigger the relays, they are overheating. When i try to trigger them sometimes they are not closing if they closed once i can't open them without power off the circuit. What can be the problem ?

Hi all, Super newbie here! I have been dabbling in electronics repair, circuit board repair, and coding for only a short time. I recently bought a used Echelon connect Cycle bike that worked but only for a short time (not under warranty). I thought I could fix it no problem, did some...

I have an IRF640 N-channel MOSFET that has no protection on the circuit, and heats up my heatsink very fast. I know I need a Zener diode to "protect" the MOSFET, but is there anything else I need, and where do I put it? CLARIFICATION: the circuit does work, but it is killing the mosfet, it heats...

I have a motherboard which does not charge the battery properly. When it is plugged into the mains, a chip labelled 2250 EmFC gets immensely hot. Please advise.

Hello I am making a power supply to power a Raspberry Pi/camera/touch screen (5V @3A), and some LEDs, servos/motors (12V LEDs and 9V servos/motors). I am using a 12V/5A adapter to supply power, and an LM2576 switching regulator to take the 12V down to 5V @3A for the pi etc. and a 7809 to drop...

Hi All, I hope that I am posting to the right forum. After days of searching, reading, experimenting, I still have not been able to find a proper solution which I can tailor to my issue, so it is time to ask you guys. I made a voltmeter which consists of an Arduino microcontroller and an...