Showing posts with label receiver. Show all posts
Showing posts with label receiver. Show all posts
Tuesday, November 18, 2014
AM Portable Receiver Using ZN414
a AM portable radio receiver using ZN414 IC. The ZN414 ic has now been replaced by the MK484 which is identical in performance and pinout.
Designed around the popular ZN414 IC this receiver covers the range of medium wave band of approximately 550 to 1600 KHz with the values indicated. The condenser coil and tuning can be taken from an old MW radio to save time. The ZN414 IC, has been replaced by the MK484. The integrated circuit is a 3 pin, tuned circuit radio frequency, and incorporates several RF stages, automatic gain control and an AM detector. Its easy to overload and voltage of th IC is critical to success.
In this circuit a small voltage regulator turns on the transistor BC108B, 1N4148 diodes four, 2k7 and 10k resistor and the resistance of pre 820R. The 10k pot control acts as a receptor selectivity for all, control the operating voltage for the ZN414 (or MK484).
The audio amplifier is built on an investment of 741 op-amp amplifier circuit. Additional current pulse is provided by the BC109C / BC179 complementary pair of transistors to drive a 8 ohm speaker. The voltage gain full audio amplifier is around 15. The audio output of the complete receiver is really good and undistorted.
Designed around the popular ZN414 IC this receiver covers the range of medium wave band of approximately 550 to 1600 KHz with the values indicated. The condenser coil and tuning can be taken from an old MW radio to save time. The ZN414 IC, has been replaced by the MK484. The integrated circuit is a 3 pin, tuned circuit radio frequency, and incorporates several RF stages, automatic gain control and an AM detector. Its easy to overload and voltage of th IC is critical to success.
In this circuit a small voltage regulator turns on the transistor BC108B, 1N4148 diodes four, 2k7 and 10k resistor and the resistance of pre 820R. The 10k pot control acts as a receptor selectivity for all, control the operating voltage for the ZN414 (or MK484).
The audio amplifier is built on an investment of 741 op-amp amplifier circuit. Additional current pulse is provided by the BC109C / BC179 complementary pair of transistors to drive a 8 ohm speaker. The voltage gain full audio amplifier is around 15. The audio output of the complete receiver is really good and undistorted.
Saturday, August 23, 2014
ZN414 Portable AM Receiver
Designed around the popular ZN414 ic this receiver covers the AM band from 550 - 1600 KHz with the values shown. For Longwave the coil needs to be changed. Use one from an old MW radio to save time. The ZN414 is a tuned radio frequency designed and incorporates several RF stages and an AM detector. It is easily overloaded and the operating voltage is critical to achieve good results.
The BC107 acts as a voltage follower, the four 1N4148 diodes providing a stable 2.4V supply. With the 10k pot , which acts as a selectivity control, and the b-e voltage drop of the BC107, the operating voltage for the ZN414 is variable from 0 to 1.8volts DC. If you live in an area that is permeated with strong radio signals, then the voltage will need to be decreased. I found optimum performance with a supply of around 1.2 volts.
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The audio amplifier is built around an inverting 741 op-amp. Extra current boost is provided using the BC109 / BC179 complementary transistor pair. The voltage gain of the complete audio amplifier is around 15. The audio output of the complete receiver is really quite good and free from distortion. I may provide some sound samples later.
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The BC107 acts as a voltage follower, the four 1N4148 diodes providing a stable 2.4V supply. With the 10k pot , which acts as a selectivity control, and the b-e voltage drop of the BC107, the operating voltage for the ZN414 is variable from 0 to 1.8volts DC. If you live in an area that is permeated with strong radio signals, then the voltage will need to be decreased. I found optimum performance with a supply of around 1.2 volts.
The audio amplifier is built around an inverting 741 op-amp. Extra current boost is provided using the BC109 / BC179 complementary transistor pair. The voltage gain of the complete audio amplifier is around 15. The audio output of the complete receiver is really quite good and free from distortion. I may provide some sound samples later.
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