Rongge

This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now no longer available. The design is simple and sensitivity and selectivity of the receiver are good. Notes: All general purpose transistors should work in this circuit, I used three BC109C transistors in my prototype.The tuned circuit is designed for medium wave. I used a ferrite rod and tuning capacitor from an old radio which tuned from approximately 550 - 1600kHz. Q1 and Q2 form a compund transistor pair featuring high gain and very high input impedance. This is necessary so as not to unduly load the tank circuit. The 120k resistor provides regenerative feedback,between Q2 output and the tank circuit input and its value affects the overall performance of the whole circuit. Too much feedback and the circuit will become unstable producing a "howling sound". Insufficient feedback and the receiver becomes "deaf". If the circuit o...

This portable AM and FM radio circuit is designed using the LA1800 IC and some other external components. As you can see in this circuit diagram the LA1800 manufactured by Sanyo Semiconductors , require few additional components. The LA1800 am FM portable radio circuit needs to be powered from a 3 volt DC power supply circuit. AM and FM Radio with LA1800 Portable Circuit Diagram You can use an 3 volt battery. This radio receiver circuit has a low current dissipation of 5.6mA for FM band and 3.2mA for AM band .Also the output signal is driven into earphone speakers , but you can use an additional speaker ( in that case you need to connect an additional small power audio amplifier).

Active AM Radio Antenna Amplifier / Preamplifier Circuit The antenna amplifier circuit has a part count of about 40, using the following active parts: 2 NPN transistors (BC548's), 1 MOSFET (BF981), 2 Varicap diodes (KV1235), as well as a 6v2 zener-diode. there is and a 330uH (micro Henry) inductor / coil, which can be modified for operation on other frequency bands. Designed to work with a telescopic whip antenna, the amplifier circuit operates in the typical AM / MediumWave band of 550 - 1650 kHz (kilohertz), with a power requirement of 12 Volts DC. The circuit also has a gain control feature, so weather signals can be amplifier more, if need be. This amplification alteration is provided via, RV1 The amplifier circuit's output impedance is 50 Ohms, which is the standard for all of radio receivers, so it ought to work well along with your AM receiver. Notes This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover t...

Here is simple Electronic Circuit Project of two transistor AM radio receiver circuit. This two transistor AM radio circuit is also called “mini-radio”. It uses only 2 transistors and few passive components which makes is very easy to be constructed. Although the circuit is very simple, it functions very well without external antenna or ground connection. The transistor T1 works as a feedback regulated HF-amplifier and function as demodulator at the same time. The sensitivity of the receiver is dependent on the amount of feedback and can be adjusted by P1. Two Transistor AM Radio Receiver Circuit Diagram: The demodulated signal comes out from the collector of T1. The signal is then filtered by C3 so that only the audio signal will be amplified by T2. The amplified signal is then delivered to a high impedance “earphone”. The coil is 65 turns AM antenna wire around a 10 cm long x 10 mm diameter ferrite rod. The tap is at the fifth turn of the coil counting from its ground end. The coil ...