Free Circuit Diagram

TDA 1072AT is a special purpose integrated circuit for AM radio receiver from Philips Semiconductors. The integrated circuit is designed for mains-fed home receivers and car radios. The voltage-controlled oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes. RF radiation and [...]

The transmitters that either working in FM or in AM is familiar. This is transmitters circuit that can transmit both FM and AM signal simultaneously at two different frequencies FM in 100Mhz and Am in 20 MHz. Here is the circuit: To transmit the FM signal, this circuit uses the 5th harmonics [...]

This antenna booster circuit can be used to amplify the weak signal received by the antenna.  Antenna for AM/FM is usually not tuned for the optimal dimension of 1/4 wavelength, since we prefer small portable size. This untuned antenna has very low gain, so the antenna booster circuit here is very helpful in getting better [...]

A PLL system can be used to implement an FM demodulator. When a PLL is locked on an FM signal, the VCO tracks the instantaneous frequency of that signal. Since the VCO output tracks the FM signal, and the VCO input voltage is proportional to the VCO output frequency, then the VCO input will be [...]

Twisted-pair wiring is a wiring technique that usually used for in-building data communication. Compared to conventional coaxial-cable, this technique offers substantial cost saving, for video transmission on the same medium. A differential driver is used to launching a baseband camera signal to twisted pair. Twisted pair exhibits a roll-off characteristic that need equalization to [...]

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, [...]