Free Circuit Diagram

LED flasher circuit here will flash a LED using only 1.5 volts  supply voltage. Normally, to make any LED lamp works, you need more than 2 volts power supply. This because LED will work only when the supply voltage is higher than its forward bias voltage, around 2 volts  for red LED, and slightly lower [...]

Classic LED Flasher Circuit This LED flasher circuit is a classic two transistor flip flop. This flasher circuit is very popular and it’s usually the first circuit to build when starting electronic circuit building hobby. Here is the schematic diagram of the famous LED flasher circuit: How LED Flasher Circuit Works [...]

This wireless microphone circuit uses only a single transistor, with few additional passive components. This FM transmitter is very compact and need only a single cell 1.5Volt battery, even works on 1.2V rechargeable battery. Here is the schematic diagram of the circuit: The transmission range could be between 30-50m radius in open air, [...]

Using only a single transistor and few passive components, you can build a fairly sensitive peak detector. circuit This peak detector circuit is suitable for audio application, since the average sum of positive and negative cycle of audio signal has equal value. You can find a peak signal although you only detect the peak of [...]

Condenser microphone and dynamic microphone (moving coil microphone) has different characteristics. For dynamic mics, a biasing current is not needed because the transducer generate the electrical signal. In condenser mics, a bias current is needed to compensate the leakage in the microphone, and because of the pre-amplifier loading that discharge the condenser mic’s electrical charges. [...]

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 [...]