Free electronic circuit design and schematic diagram
This transistor tester is very helpful if you need to sort bulk transistors. In some market, if you know where to find it, sometimes you can get transistors sold in kg unit, not in single peaces unit. You can buy 1 kg of transistors with really cheap prices. Don’t be too happy right now because you have to be careful, […]
Read more
The frequency formula of 555 oscillator is popularly known. For a known resistors and capacitor, the frequency can be determined by a formula. From the math logic, if the frequency and the resistors are known, then an unknown capacitor could be determined by the inverse of the formula. Anyone who has a frequency counter are able to use the following […]
Read more
Many efforts has been made to make simpler circuit, and here is one result, a very simple touch switch. You can build up to 6 similar circuit using only one 4050 chip. If you touch the “on” pad, the output will be on on remains on until you or some one the “off” pad. Here is the circuit schematic diagram: […]
Read more
Using only a single chip and few passive components, you can build 8-14 Watt audio power amplifier using TDA2030 chip. Here is the circuit schematic diagram: If you use 4 ohm speaker then you get 14 Watt output power, and around 8 Watt if you use 8 ohm loudspeaker. Make sure the 100n and 100u capacitor is wired as close […]
Read more
Don’t worry if you need a symmetric power supply and you don’t have a center tapped transformer. The circuit below solve your problem. You can see the second bridge diode is powered via capacitor decoupling, so it’s DC isolated. Because it’s DC isolated, we can connect the ground together to form a symmetric supply. Because the second rectifier is powered […]
Read more
It seems that center tapped transformer with a bridge diode is common solution to provide symmetric power supply, but we can actually do it with simpler solution, using a voltage doubler – rectifier diodes. You can see this simple circuit in the figure. The capacitor need to be large because the rectifying is half wave, so you can avoid power […]
Read more
Ibanez Fat Cat distortion pedal (Ibanez FC-10 Fat Cat Distortion) is good for blues, rock, pop, alternative, but not for metal. You can hear the fat tone even at maximum overdrive. Here is the circuit schematic diagram. You can see the the first transistor 2SC1815/BC546 is configured as voltage follower, giving a high impedance for the input. The op-amp (5534 […]
Read more