# Electric circuit diagram proof check - simple

I'm completely new in this field (electronics, I began today) and therefore I am quite the newcomer and would like to know if I understood the purpose of the transistors and capacitors and the diagram in a whole.

This diagram is made for a remote controlled electronic electromagnetic toy crane.

LOAD 5 is the part where the electromagnet is supposed to be.

The crane is made out of primary scrap parts and therefore I do not know the voltage of the battery yet.

Diagram:

simulate this circuit – Schematic created using CircuitLab

My current understanding of the transistors and capacitors:

A NPN transistor can work like a switch. If at the base is applied a current it will allow the current from the collector to be emitted out through the emitter.

A PNP transistor can also work like a switch, if at the base there isn't applied a current it will allow the current from the collector to flow out of the emitter.

A capacitor can be used to stabilise the current and work as a backup source if the voltage drops aka it will try to make the current stay constant.

So to sum it up:

• Would this work?
• Did I use the transistors correctly?
• Did I use the capacitors correctly?
• You're coming on quickly and +1 for the schematic. Unfortunately you've skipped a few lessons in basic transistor theory, some of your statements aren't correct and there are a few problems with the layout. I'll leave it to others to help you this time. Bedtime where I live. Meanwhile look up H-bridge for DC motor. Commented Jul 11, 2016 at 21:57
• Your NPN description is roughly correct. If Base voltage is ca. 0.6 v higher than emitter voltage , current will flow and NPN will conduct. Your PNP description is incorrect. No Base current means no conduction. Commented Jul 11, 2016 at 22:49
• So what you are saying is: NPN - If the voltage in the base is 0.6 V higher the current will flow. PNP - If there is a current it will flow? Commented Jul 11, 2016 at 23:00
• By inspection, NPN transistors Q1 through Q5 are operating in forward active mode (signal amplifier mode) and not saturation mode (switch ON mode). Ordinarily, you want these transistors to operate like ON/OFF switches (saturation/cutoff modes) and not as signal amplifiers (forward active mode). Note that there is a voltage drop across the components that are connected to the emitter of each NPN transistor. That voltage drop causes negative feedback which prevents the transistor from saturating; thus the transistor is stuck in forward active mode when it is "on". Commented Jul 12, 2016 at 6:23
• When using a bipolar transistor as a switch, connect the emitter directly to the power supply. For NPN transistors, connect the emitter directly to the power supply's NEGATIVE terminal. For PNP transistors, connect the emitter directly to the power supply's POSITIVE terminal. For MOSFETS, remember "SOURCE to SUPPLY", and again, NMOS's source to NEGATIVE supply, and PMOS's source to POSITIVE supply. Commented Jul 12, 2016 at 6:25