This is the FM transmitter circuit which apply 4 radio frequency stages, that are a VHF oscillator designed around transistor BF494 (T1), a preamplifier designed around transistor BF200 (T2), a driver designed around transistor 2N2219 (T3) and also a power amplifier designed around transistor 2N3866 (T4). A condenser microphone is wired at the input of… Read More »
This is the circuit diagram of seismic / vibration sensor. The circuit simulates a seismic sensor to detect vibrations/sounds. It’s really sensitive and may detect vibrations due to the motion of animals or human beings. So it could be utilized to monitor protected locations to restrict entry of undesirable individuals or animals. The circuit applies… Read More »
This two chips AM radio receiver circuit is a tuned radio frequency (TRF) receiver of the standard AM (amplitude modulation) radio with broadcast frequencies at 550kHz-600kHz. This is a simple and easy to build AM radio circuit which only using two integrated circuits (IC). This circuit works with 9V voltage supply, you could use 9V… Read More »
The following diagram is the schematic diagram of 4 transistors FM transmitter circuit designed by Paul K. Sherby. Components List: R1,R2,R8 = 1K R3 = 100K R4 = 150K R5,R7 = 10K R6 = 220 ohm R9 = 10 ohm P1 = 5K trimpot D1 = 1N4002 Q1,Q2 = 2N3904 Q3,Q4 = 7001, NTE123AP C1… Read More »
In the above circuit diagram, a CMOS operational amplifier (op-amp) controls the current via a P-Channel HEXFET power transistor (IRF9520) to maintain a constant voltage across R1. The current is given by: 1 = VREF/R1. The benefits of this configuration are:
Below circuit is the tone booster circuit. According to the name of circuit, the purpose is to amplify the sound signal to become more powerful in both low and high frequencies. There is no potensiometer used for bass/treble adjustment. Transistor type: Q1 – ztx384 ; Q2 – BC415p The circuit’s peaks frequencies is at 5000… Read More »
The following diagram is the circuit diagram of low cost 12V stereo tone control which also available in kit, you may find the kit at electronic part store around your place. The circuit build based on ordinary tone control circuit, using two low cost transistors FCS9014 in each channel, so there are will be four… Read More »
The following image is the scheme diagram of six LED stereo VU display circuit which build using Dot/Bar Display Driver IC LM3915. This VU display should be connected before amplifier module circuit. You may connect this circuit at pre-amp output, tone control input/output or equaliser input/output. This circuit powered with 12V DC supply. About LM3915:… Read More »
The following diagram is the circuit diagram of 20 band stereo graphic equaliser which will controlling the audio signal in specific frequency range. The power supply used for this circuit is symmetrical (dual polarity) type, 15V DC.