nº896

Minimalist alarm siren: 1 resistor + 1 BJT + 1 blue led + 2 capacitors + 1 loudspeaker, supply 9V

nº895

Minimalist multivibrator for dual(red/green) led : 2 transistors + 1 trimmer potentiometer + 1 capacitor, supply 2xNiMH.

nº894

Simple voice changer with 4 transistors, supply 2xNiMH.

nº893

Sound effect "deep breathing" with 4 transistors, supply 9V.

nº892

Yellow led driven by 1 bipolar transistor operates in 2 modes: irregular flickering or always on; supply 2xNiMH.

nº891

The clap latch with 3 bipolar transistors, supply 3V.

nº890

C-L-C oscillator with JFET transistor.

nº889

Wireless receiver activates wireless transmitter when they are closely aligned otherwise wireless transmitter sends a beacon with minimum current consumption, supply 1xNiMH.

nº888

Beep-Beep alarm with 1 transistor + 1 resistor + 1 LED + 2 capacitors, supply 12V.

nº887

Intermittent beacon for the MW band with 1 bipolar transistor, supply 2xNiMH.

nº886

Experimental alarm with 5 yellow leds and 1 bipolar transistor, supply 12V.

nº885

Beep-beep alarm with 1 bipolar transistor and 1 yellow led, supply 2xNiMH.

nº884

Smart cooling fan. Forced air flows to the side where temperature is higher, supply 12V.

nº883

Simple metal detector with 1 transistor operating in the MW radio band, supply 2xNiMH.

nº882

Incandescent lamp automatic fading up and down with RC oscillator, supply 230Vac/50Hz.

nº881

RLC joules thief with photocell by led light sensing.

nº880

Simple 2kHz beep-beep alarm with 1 bipolar transistor, supply 2xNiMH.

nº879

Simple mains supplied latch switch with single led-led photo interrupter.

nº878

Resistors cube equivalent resistance.

nº877

Simple white led bar(2x3) with photocell feature by rectifier diode light sensing, supply 3xNiMH.

nº876

Combined led bar and sound effect with 1 transistor, supply 12V

nº875

Beep-Beep alarm with 1 NE555N, supply 4,5V

nº874

Bip-bip alarm with 1 NE555 timer, supply 5V

nº873

Minimalist buzzer with 1 NE555 timer + 1 resistor + 1 piezoelectric speaker, supply 5V

nº872

Simple 1 transistor red led bar with 2 operating modes: oscillating / permanently ON; supply 12V

nº871

Simple led ring oscillator with 7 stages, supply 230Vac/50Hz

nº870

Very low frequency oscillator with 1 transistor drives 12V/5W incandescent bulb with low value timing capacitors, supply 12V

nº869

Blinking mini incandescent lamp(3V) with 1 bipolar transistor, supply 1xNiMH

nº868

Minimalist mini incandescent lamp sequencer, supply 12V

nº867

Variable voltage divider

nº866

Up and down fading of 12V/5W incandescent lamp with 1 bipolar transistor, supply 12V

nº865

nº864

Mains supplied doorbell with 4 components is activated with smartphone led lantern.

nº863

Prototype of simple capacitance meter for oscilloscope. Measured capacitor is 68pF. Oscilloscope time base is 20uS/div.

nº862

Prototype of car turn light with 5 leds, supply 12V.

nº861

Experimental car turn light indicator with 5 yellow leds and 1 transistor, supply 12V.

nº860

Experimental LW/MW TRF audion receiver with 2 bipolar transistors and tuning with varicap diode, supply 9V.

nº859

Simple 12V/5V-100mA self-oscillating buck converter with 1 transistor (switch) and 1 optocoupler. (PWM control)

nº858

Simple BTL class A amplifier based on dual op-amp LM358N drives 110 Ohm loudspeaker with 1.1Vpp sinewave under 2xNiMH power supply.

nº857

Complete experimental MW radio receiver based on dual op-amp LM358N. Envelope detector wtih OA5 Ge diode, 2mts wire antenna + PE connection; supply 2xNiMH

nº856

Simple thermometer with 1 transistor + 1 resistor + 1 trimmer potmeter, supply 2xNiMH