problem

I'm trying to make a VCO from this schematic but I can't get it to work. My oscilloscope broke so I can't use it but when I plug in my headphones I only hear a slight DC voltage. (The circuit runs on a single supply)

Hi, I'm a physics student, and I have a small problem for a lab that I have to solve. Here is my problem: I must create a circuit which uses capacitors to gradually close a light, but in addition, we must pass the current from the capacitor which discharges by the base of an NPN transistor. A...

Hi, I created a low-ohm meter circuit similar to the one described here : https://www.allaboutcircuits.com/projects/build-your-own-low-resistance-meter/ for measuring the contact resistance on a Relay. However the relay's i'm checking have upto 16 contacts, so I created multiples of the...

Hi, I have a problem, In the following circuit, I have a voltage regulator with a selector that chooses between different resistor values to make different voltages. But if ever the selector malfunctions or when changing, it will be disconnected, so the circuit will be open and the voltage...

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Hello, About a year ago I bought a Muff Guitar pedal project from Bitsbox. It was working well untill it broke last week. I took it apart and noticed the ground wire coming from the output has been pulled out of the board (the output became lose and must have spun enough to pull this off). Now...

Detailed description and website link are below. Parameter: 1>.Product Name: pWM 4-Wire Fan Temperature Controller 2>.Work Voltage: DC 11V~55V 3>.Work Current: 0.1A(MAX) 4>.Fan Current: 5A(MAX) 5>.PWM Range: 5%~100% or 0% 6>.PWM Frequency: 20KHz/2.5KHz 7>.PWM Signal Amplitude...

Hello i have a wellhise wh-890d multimeter. Yesterday i was trying to charge a motorbike 12v battery i unplugged the charger to check voltage then i checked the amp it is taking then i forgot the probe was in the amp hole (left 20A hole on the photo) then i put the meter on voltage mode and i...

Hello, my treadmill pro-form 530zlt got burned control board. It has MC2100ELS-18W control board driving this motor. I'm stuck in difficult situation as after getting board running again motor has no torque, I can stop it by hand. I noticed that commutator brushes are giving noise and sparks...

Hi everybody !! Well, I recently made the famous LM358-based VCO as in this article : https://www.allaboutcircuits.com/projects/diy-synth-series-vco/ Everything seems to work fine except those buffers which I can't get to work at all and I just can't understand why ... I've already tried...