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

nº855

USB dummy loads and micro-USB to standard USB A receptacle adapter. Suitable for connecting USB standard connector 1A dummy load to universal Qi 5W wireless receiver type A/B with micro-USB connector.

nº854

Constant current, adjustable(up to 1A) dummy load for Li-ion batteries. For 100% discharge from 4,2V downto 3V. Discharge current is 1mA per mV measured. Supply 9V. No current drift during discharge. Led off means stopped discharge.

nº853

Experimental board for simple lithium-ion battery capacity tester with constant current dummy load adjustable up to 500mA. supply 5V.

nº852

Li-ion/Lipo battery cell simple capacity tester:
- Discharges @1C for batteries up to 500mAh.
-Stops discharge @ 3V (led OFF).
- C=Id(mA)xT(h).

nº851

Method for transforming polar electrolytic capacitors into non-polar capacitor.

nº850

- Mains voltage detector, supply 1xNiMH.
- Detector de tensão de rede, alimentação 1xNiMH.

nº849

Lithium ion battery charge(4,20V)/discharge(3V) protection with 2 bipolar transistors. Supply >=5V.

nº848

The ferrite bead led torch with 8 white leds, supply 1xNiMH. Low component count.

nº847

Inverter and non-inverter logarithmic amplifier.

nº846

- Simple toroid "joules thief"for violet led.
- "Ladrão de joules" simples por toroide para led violeta.

nº845

Dummy load for wireless near field (inductive coupling) power receiver.

nº844

Sample of simple joules thief with ferrite bead.

nº843

Simple timer; Toff=15min-24h; Ton=15min-24h. The binary counter switches between NE556 astable multivibrators every 8192th clock negative transition.

nº842

Two simple examples of 1 pulse voltage multiplier.